No full-text available
To read the full-text of this research,
you can request a copy directly from the author.
Congenital Spinal Lipomatous Malformations. Part 2. Differentiation from Selected Closed Spinal Malformations
Abstract
Background. Congenital spinal lipomatous malformations (spinal lipomas, lipomyeloceles, and lipomyelomeningoceles) are closed neural tube defects over the lower back. Differentiation from some other closed neural tube defects in this region can be problematic for pathologists.
Materials and Methods. This review is based on PubMed searches of the embryology, gross and histopathologic findings, and laboratory reporting requisites for retained medullary spinal cords, coccygeal medullary vestiges and cysts, myelocystoceles, true human vestigial tails, and pseudotails for comparison with congenital spinal lipomatous malformations.
Results. Embryology, imaging, gross and histopathology of these closed neural tube lesions have different but overlapping features compared to congenital spinal lipomatous malformations, requiring context for diagnosis.
Conclusion. The lipomyelocele spectrum and to some degree all of the malformations discussed, even though they may not share gross appearance, anatomic site, surgical approach, or prognosis, require clinical and histopathologic correlation for final diagnosis.
Background
Open spina bifida is an uncommon malformation in animals, and there is a lack of imaging, clinical, and pathological characterisation of this condition in dogs.
Objective
Open spina bifida is rarely observed in animals due to high levels of perinatal mortality and frequent euthanasia. To the best of our knowledge, we present the first case of spina bifida in a dog was diagnosed in‐utero and then followed post‐partum.
Methods
A 3‐year‐old Poodle was presented with twin pregnancy. Radiographic and ultrasonographic findings were suggestive of vertebral malformation and open spina bifida with myelomeningocele in one foetus. Conservative treatment was given but the puppy died 3 days after birth. Thereafter, anatomical and histopathological analysis of several organs was performed to characterise the disease.
Results
When the twins were born, one puppy had a linear dorsal midline cutaneous defect extending from the level of vertebrae L2–L6. R Radiographic examination showed several congenital vertebral malformations involving the thoracic segment, lumbar segment, sacrum and scapula. Histopathological examinations confirmed the presence of open spina bifida and identified additional abnormalities in several internal organs.
Conclusions
This case presents a complete characterisation of open spina bifida, before birth and after death, using imaging and histopathology techniques.
Chaotic lipomas are an extremely rare variant of spinal lipomas. This entity was first defined in 2009 by Pang and colleagues. Not much has been written about this variant. Its characteristic is the haphazard distribution of DREZ (Dorsal root entry zone), nerve roots and placode-lipoma interface. Thus complete/near-total excision of this lesion is quite difficult. We describe a case of chaotic spinal lipoma and elucidate the challenges faced in the management of this entity and review the literature. We performed a thorough systematic review with the keyword ‘chaotic’, ‘Lipomyelomeningocele’, ‘Complex Lipomyelomeningocele’, ‘LMMC’, ‘Lumbar lipoma’, ‘spinal lipoma’ in the google scholar and PUBMED data system for indexed literature on the above topic with no particular time frame. The studies quoted range earliest from 1970 till currently. Additional potential relevant articles were further retrieved through a manual search of references from original reports. Out of 42 studies, a total of 21 publications were selected which could have encountered a chaotic variant, but due to the term introduced only recently in 2009, may have been described differently. Studies encompassing true lipomeningomyelocele were excluded from our review. What we found out? Chaotic lipoma may not be a new entity. The scarce description in literature may be in part due to non-introduction and unclear description of this term earlier. The management of this variant is particularly challenging with basic principles remaining the same. Meticulous near-total excision and placode-lipoma construct are the major obstacles.
Spinal dysraphism is an umbrella term that encompasses a number of congenital malformations that affect the central nervous system. The etiology of these conditions can be traced back to a specific defect in embryological development, with the more disabling malformations occurring at an earlier gestational age. A thorough understanding of the relevant neuroembryology is imperative for clinicians to select the correct treatment and prevent complications associated with spinal dysraphism. This paper will review the neuroembryology associated with the various forms of spinal dysraphism and provide a clinical-pathological correlation for these congenital malformations.
Background: Lumbosacral spinal lipomas and lipomyeloceles are usually identified in early childhood. Terminology, histopathology, and diagnosis for these malformations can be confusing. Materials and Methods: This is a PubMed review with comparison of embryology, gross, and histopathology, and reporting requisites for these and related closed spinal malformations. Results: The spinal lipoma group (congenital spinal lipomatous malformations) includes subcutaneous, transdural, intradural, and noncontiguous malformations stretching through the entire lower spinal region. This lipomyelocele trajectory overlaps the embryonic tail’s caudal eminence. Histopathologically, the lipomyelocele spectrum is a heterogeneous, stereotypical set of findings encountered from dermis to spinal cord. Diagnosis requires detailed correlation of images, intraoperative inspection, and histopathology. Conclusions: Appropriate terminology and clinicopathologic correlation to arrive at a diagnosis is a critical activity shared by pathologist and clinician. Prognostic and management differences depend on specific diagnoses. Familial and genetic influences play little if any role in patient management in closed spinal malformations.
Homo naledi is a previously-unknown species of extinct hominin discovered within the Dinaledi Chamber of the Rising Star cave system, Cradle of Humankind, South Africa. This species is characterized by body mass and stature similar to small-bodied human populations but a small endocranial volume similar to australopiths. Cranial morphology of H. naledi is unique, but most similar to early Homo species including Homo erectus, Homo habilis or Homo rudolfensis. While primitive, the dentition is generally small and simple in occlusal morphology. H. naledi has humanlike manipulatory adaptations of the hand and wrist. It also exhibits a humanlike foot and lower limb. These humanlike aspects are contrasted in the postcrania with a more primitive or australopith-like trunk, shoulder, pelvis and proximal femur. Representing at least 15 individuals with most skeletal elements repeated multiple times, this is the largest assemblage of a single species of hominins yet discovered in Africa.
Purpose:
The term limited dorsal myeloschisis (LDM) was used by Pang et al. (2010) to describe a distinct clinicopathological entity. LDMs are characterized by two invariable features: a focal-closed neural tube defect and a fibroneural stalk that links the skin lesion to the underlying spinal cord.
Methods:
We retrospectively analyzed the neurosurgical pathologic findings of four LDM patients.
Results:
Case 1 had a saccular skin lesion with nonterminal abortive myelocystocele at T11-12. Cases 2, 3, and 4 had a non-saccular (flat) skin lesion in the lumbosacral region. The morphologic features of the lesion in case 2 were those of meningocele manque. Cases 3 and 4 had accompanying non-LDM anomalies, caudal-type lipoma and type II split-cord malformation with neurenteric cyst, respectively. At preoperative diagnosis of the LDM stalk, magnetic resonance imaging, including 3D heavily T2-weighted image was useful; however, minute findings were often missed in the complicated cases 3 and 4. All patients had a favorable outcome following untethering of the stalk from the cord. The central histopathological feature of the LDM stalk is neuroglial tissue in the fibrocollagenous band; however, the stalk in cases 2 and 4 did not have glial fibrillary acidic protein-immunopositive neuroglial tissues.
Conclusions:
Therefore, the diagnosis of LDM should be made based on comprehensive evaluation of histologic and clinical findings.
Introduction:
Limited dorsal myeloschisis (LDM) originates from undisjointed neural and cutaneous ectoderms during primary neurulation. Its hallmark is a fibroneural stalk causing tethering on the dorsal spinal cord rostral to the conus. Its treatment is a relatively straightforward resection of the LDM stalk from the spinal cord.
Methods and results:
On reviewing our series of 75 cases of LDMs, we found that the majority of LDM stalks have only a glioneuronal core within a fibrous stroma, but a small number have been found to have elements of dermoid cyst or a complete dermal sinus tract either contiguous with the fibroneural stalk or incorporated within its glial matrix, not surprising considering the original continuum of cutaneous and neural ectoderm in LDMs' embryogenesis. The dermoid element can be microscopic and escape casual observation, but could grow to large intradural dermoid cysts if part of the dermoid invested LDM stalk is left inside the dura.
Conclusions:
We present our series of LDMs associated with dermoid elements and recommend excising the entire length of the intradural LDM stalk from its dural entry point to its merge point with the spinal cord during the initial treatment to avoid secondary deterioration and additional surgery.
Introduction:
The most commonly used classification system for caudal appendages (aka human tails) dates from the 1980s and classifies appendages (tails) as either true tails or pseudotails. Advances in neuroimaging since the 1980s, however, as well as an ever-increasing number of reported cases, have made this system outdated. Sacrococcygeal eversion is a condition in which the distal sacral and coccygeal vertebrae are curved in a retroverted rather than anteverted direction. It can give rise to one type of caudal appendage. Sacrococcygeal eversion has never been associated with spinal cord tethering in any previously published reports.
Methods:
We reviewed all cases of caudal appendage encountered by pediatric neurosurgeons at Children's Hospital Colorado since 2000 in which the appendage would be classified as a true tail by the most commonly used system mentioned above. We also reviewed cases of sacrococcygeal eversion encountered since 2000 by the same group of pediatric neurosurgeons. We searched the hospital electronic medical record system for additional appendages using the terms "caudal appendage" and "persistent human tail."
Results:
We found 9 "true" tails (as classified by the most commonly used system). All 9 were associated with tethering or possible tethering of the spinal cord and 6 were associated with a low-lying conus medullaris. There were 8 cases of sacrococcygeal eversion, including 2 associated with Apert or Pfeiffer syndrome and fibroblast growth factor receptor 2 (FGFR2) mutations; these have previously been reported. There was a single case of sacrococcygeal eversion associated with Goldenhar or Turner syndrome; the former was associated with a potentially tethering lesion. Four cases of sacrococcygeal eversion not associated with any known syndrome were also found; two of these were associated with tethering or potentially tethering lesions.
Conclusions:
Most so-called true tails are likely cutaneous markers for spinal dysraphism and spinal cord tethering and are not remnants of the embryonic human tail. Sacrococcygeal eversion can be associated with spinal cord tethering. Based on our cases, and on review of the literature, we devised a five-category classification system for caudal appendages: (1) soft-tissue caudal appendages, (2) bony caudal appendages, (3) bony caudal prominences, (4) true tails, and (5) "other" caudal appendages.
A human tail or a caudal appendage is a rare condition with preconceived notions and stigmata. They could be either true tails or "pseudotails" based on their embryology. Clinically, they are considered as a marker of occult spinal dysraphism. We report two such cases with tethering of cord, one of which was associated with a lipomeningomyelocele. These patients are in need of meticulous evaluation and appropriate management.
A pseudo-tail is defined as a tail-like lesion in the lumbosacrococcygeal region that is not a true tail but one caused by disease. Perineal lipoma is one of the conditions that may present as a pseudo-tail. Congenital perineal lipoma is a rare disease and in particular, isolated congenital perineal lipoma without other anomalies is extremely rare. Here we report a case of congenital isolated perineal lipoma presenting as a pseudo-tail and also include a literature review of the condition.
Upright walking absent a bent-hip-bent-knee gait requires lumbar lordosis, a ubiquitous feature in all hominids for which it can be observed. Its first appearance is therefore a central problem in human evolution. Atelids, which use the tail during suspension, exhibit demonstrable lordosis and can achieve full extension of their hind limbs during terrestrial upright stance. Although obviously homoplastic with hominids, the pelvic mechanisms facilitating lordosis appear largely similar in both taxa with respect to abbreviation of upper iliac height coupled with broad sacral alae. Both provide spatial separation of the most caudal lumbar(s) from the iliac blades. A broad sacrum is therefore a likely facet of earliest hominid bipedality. All tailed monkeys have broad alae. By contrast all extant apes have very narrow sacra, which promote “trapping” of their most caudal lumbars to achieve lower trunk rigidity during suspension. The alae in the tailless proconsul
Ekembo nyanzae
appear to have been quite broad, a character state that may have been primitive in Miocene hominoids not yet adapted to suspension and, by extension, exaptive for earliest bipedality in the hominid/panid last common ancestor. This hypothesis receives strong support from other anatomical systems preserved in
Ardipithecus ramidus
.
Terminal myelocystocele (TMC) is a rare form of spinal dysraphism. They constitute approximately 5% of skin covered lumbosacral masses. The TMC is composed of a low-lying conus medullaris with cystic dilatation of caudal central canal and a surrounding meningocele that extends from the conus to the skin. A 2-year-old female child presented with a large lumbosacral mass and weakness of both lower limbs since birth. Magnetic resonance imaging revealed a giant TMC. The child was operated on successfully. This is an interesting and rare case of "giant" TMC with partial sacral agenesis.
Australopithecus fossils were regularly interpreted during the late 20th century in a framework that used living African apes, especially chimpanzees, as proxies for the immediate ancestors of the human clade. Such projection is now largely nullified by the discovery of Ardipithecus. In the context of accumulating evidence from genetics, developmental biology, anatomy, ecology, biogeography, and geology, Ardipithecus alters perspectives on how our earliest hominid ancestors--and our closest living relatives--evolved.
The fossil record of the human pelvis reveals the selective priorities acting on hominin anatomy at different points in our evolutionary history, during which mechanical requirements for locomotion, childbirth and thermoregulation often conflicted. In our earliest upright ancestors, fundamental alterations of the pelvis compared with non-human primates facilitated bipedal walking. Further changes early in hominin evolution produced a platypelloid birth canal in a pelvis that was wide overall, with flaring ilia. This pelvic form was maintained over 3-4 Myr with only moderate changes in response to greater habitat diversity, changes in locomotor behaviour and increases in brain size. It was not until Homo sapiens evolved in Africa and the Middle East 200 000 years ago that the narrow anatomically modern pelvis with a more circular birth canal emerged. This major change appears to reflect selective pressures for further increases in neonatal brain size and for a narrow body shape associated with heat dissipation in warm environments. The advent of the modern birth canal, the shape and alignment of which require fetal rotation during birth, allowed the earliest members of our species to deal obstetrically with increases in encephalization while maintaining a narrow body to meet thermoregulatory demands and enhance locomotor performance.
© 2015 The Author(s) Published by the Royal Society. All rights reserved.
Cerebrospinal fluid (CSF) has attracted interest as an active signaling milieu that regulates brain development, homeostasis, and course disease. CSF is a nutrient-rich fluid, which also contains growth factors and signaling molecules that regulate multiple cell functions in the central nervous system (CNS). CSF constitution is controlled tightly and constituent concentrations are maintained narrow, depending on developmental stage. From fetal stages to adult life, CSF is produced mainly by the choroid plexus. The development and functional activities of the choroid plexus, and other blood-brain barrier systems in adults, have been extensively analyzed. However, the study of CSF production and homeostasis in embryos from the closure of the anterior neuropore, when the brain cavities become physiologically sealed, to the formation of the functional fetal choroid plexus has been largely neglected. This developmental stage is characterized by tightly controlled morphological and cellular events in the anterior part of the CNS, such as rapid brain anlagen growth and initiation of primary neurogenesis in the neural progenitor cells lining the cavities, events which are driven by specific molecules contained within the embryonic CSF. In this article, we review the existing literature on formation and function of the temporary embryonic blood-CSF barrier, from closure of the anterior neuropore to the formation of functional fetal choroid plexuses, with regard to crucial roles that embryonic CSF plays in neural development.
A retained medullary cord (RMC) is a rare dysraphic malformation, recently described as a late arrest of secondary neurulation. RMC is also a severely tethering lesion. The critical role of intraoperative neurophysiology to safely manage a RMC has been only anecdotally reported.
We describe the case of a RMC in a 1.5-year-old child with Currarino syndrome. At surgery, an apparently normal-looking spinal cord, stretched and tethered by a lipoma to the level of S2-S3, was observed. The border between the functional conus and the non functional RMC was defined through neurophysiological mapping. The cord was sharply interrupted at this level and untethered. A specimen was sent for pathology, which confirmed the presence of glial and neural elements. The post-operative neurological exam was normal.
Neurosurgical procedure for RMC should only be rendered with intraoperative neurophysiological mapping, as the anatomical judgment would not suffice to allow a safe cutting of these "normal-looking" neural structures.
Spina Bifida occulta usually presents with some cutaneous stigmata e.g. hair patch, sinus, lipoma, hyperpigmented skin and very rarely a congenital tail. A congenital tail may and may not be associated with spina bifida occulta and tethered cord. A four month old male child presented with congenital tail which was associated with spinal dysraphism and caused tethering of the cord itself. The tail and tethering lesion were excised successfully.
We present a complex case of dorsolumbosacral agenesis associated with a nonterminal myelocystocele and secondary tonsillar herniation. The secondary tonsillar herniation, mimicking a Chiari I malformation, was evident at postnatal life with concomitant enlargement of the myelocystocele. Prenatal and postnatal MRI proved invaluable in recognizing temporal change in the position of the cerebellar tonsils. Postmortem examination confirmed the presence of a nonterminal myelocystocele and dorsolumbosacral agenesis. © 2013 S. Karger AG, Basel.
A female baby was born at 37 weeks and 6 days gestation by vaginal delivery with omphalocele, exstrophy of the cloaca, and imperforate anus, indicating the presence of OEIS complex, a rare combination of defects consisting of omphalocele (O), exstrophy of the cloaca (E), imperforate anus (I), and spinal deformity (S), associated with lumbosacral lipoma. The most common associated spinal deformity is terminal myelocystocele, and spinal lipoma is rare. Constructive interference in steady-state magnetic resonance imaging clearly revealed double lipomas, a dorsal-type lipoma, located dorsal to the low-lying conus medullaris, and a filar-type lipoma, revealed by a thickened and fatty filum terminale. After recovery from abdominogenital repairs, debulking of the dorsal-type lipoma and untethering of the spinal cord by sectioning of the filar-type lipoma were performed at the age of 14 months. Neurosurgical treatment for occult spinal dysraphism should be undertaken after recovery from the initial series of major abdominogenital procedures.
Limited dorsal myeloschisis (LDM) is a distinctive form of spinal dysraphism characterized by a focal midline neural tube defect associated with tethering of the dorsal spinal cord to the overlying skin (1-4). Since prenatal diagnosis is rare, we stress in this letter the importance of distinguishing it from myelomeningocele as they have a very different prognosis.
The chronological scenario of the evolution of hominoid primates has been thoroughly investigated since the advent of the molecular clock hypothesis. With the availability of genomic sequences for all hominid genera and other anthropoids, we may have reached the point at which the information from sequence data alone will not provide further evidence for the inference of the hominid evolution timescale. To verify this conjecture, we have compiled a genomic data set for all of the anthropoid genera. Our estimate places the Homo/Pan divergence at approximately 7.4 Ma, the Gorilla lineage divergence at approximately 9.7 Ma, the basal Hominidae divergence at 18.1 Ma and the basal Hominoidea divergence at 20.6 Ma. By inferring the theoretical limit distribution of posterior densities under a Bayesian framework, we show that it is unlikely that lengthier alignments or the availability of new genomic sequences will provide additional information to reduce the uncertainty associated with the divergence time estimates of the four hominid genera. A reduction of this uncertainty will be achieved only by the inclusion of more informative calibration priors.
Terminal myelocystocele is a rare spinal dysraphism that present as lumbosacral mass. Magnetic resonance imaging (MRI) is the modality of choice for preoperative diagnosis. A 2.5 months old female baby presented with lumbosacral skin covered mass. There were no associated neurological deficits. MRI of the lesion suggested two cysts, one of which was continuous with the central canal of the spinal cord. At operation terminal myelocystocele was found with tethering of the spinal cord. Untethering of the spinal cord and repair of the myelocystocele performed with uneventful recovery.
We report a female infant who presented with a tail appendage bearing a gelatinous tip and an associated lipomyelocele. Magnetic resonance images revealed the presence of spina bifida and a tract in continuity from the tail to the conus medullaris. The tail was surgically removed. A human tail may be associated with underlying spinal dysraphism. Magnetic resonance or computed tomographic imaging is required in such cases for complete evaluation. This is the first case report of gelatinous-tip human tail.
Human tail is a curiosity, a cosmetic stigma and presents as an appendage in the lumbosacral region. Six patients of tail in the lumbosacral region are presented here to discuss the spectrum of presentation of human tails. The embryology, pathology and treatment of this entity are discussed along with a brief review of the literature.
A case report.
To report on an interesting case of a symptomatic human pseudo tail in a 7-year-old girl, who had a lordotic deformity of the coccyx due to partial segmentation.
Caudal appendages are uncommon congenital malformations classified into two categories, true tails and pseudo tails, usually treated by surgical resection. Protrusion of the coccygeal vertebrae is considered the most common cause of pseudo tail.
Summary of the surgical management, as well as an x-ray film of the coccyx 8 years postoperatively, is presented.
Total resection of the coccyx was successfully performed and all preoperative complaints of the patient were resolved shortly after the surgery. Follow-up 8 years later revealed regrowth of a small coccygeal bone, in normal alignment.
Segmentation failure of the coccyx vertebrae may lead to an abnormal position of the coccyx that may interfere with daily life and therefore require coccygectomy. A newly developed coccygeal bone, in normal alignment, may be present at site after several years.
Myeloschisis is the most serious and complex congenital anomaly in spina bifida manifesta (cystica). However, with improvements in medical care and increased understanding of its pathophysiology, the associated long-term morbidity and mortality rates have been significantly reduced. This article reviews various issues associated with the neurosurgical management of patients with myeloschisis, such as perinatal management, repair surgery for myeloschisis, neurosurgical management of hydrocephalus, Chiari malformation type II, tethered cord syndrome and epilepsy, and intrauterine fetal surgery.
A true human tail is a rare occurrence and is defined as a caudal, vestigial, midline protrusion with skin covering connective tissue, muscle, vessels and nerves. We report a case of true human tail in a child, which is a very rare happening in humans.
Background: Lumbosacral spinal lipomas and lipomyeloceles are usually identified in early childhood. Terminology, histopathology, and diagnosis for these malformations can be confusing. Materials and Methods: This is a PubMed review with comparison of embryology, gross, and histopathology, and reporting requisites for these and related closed spinal malformations. Results: The spinal lipoma group (congenital spinal lipomatous malformations) includes subcutaneous, transdural, intradural, and noncontiguous malformations stretching through the entire lower spinal region. This lipomyelocele trajectory overlaps the embryonic tail’s caudal eminence. Histopathologically, the lipomyelocele spectrum is a heterogeneous, stereotypical set of findings encountered from dermis to spinal cord. Diagnosis requires detailed correlation of images, intraoperative inspection, and histopathology. Conclusions: Appropriate terminology and clinicopathologic correlation to arrive at a diagnosis is a critical activity shared by pathologist and clinician. Prognostic and management differences depend on specific diagnoses. Familial and genetic influences play little if any role in patient management in closed spinal malformations.
Background:
Lumbosacral and coccygeal skin covered appendages are a rare malformation, considered human-tails.
Case report:
The authors describe the case of a full term newborn girl with lumbar skin appendage and a normal neurologic examination. The magnetic resonance of the spine revealed a dermal sinus continuous with the skin appendage and with extension into to the spinal canal. Due to the infection risk, a surgery was performed on the third day of life, with dermal sinus ligation and appendage removal. At 12 months of follow-up the girl has a normal neurologic examination.
Conclusions:
With the description of this case the authors aim to emphasize that although rare, lumbar skin appendages can be associated with spinal dysraphism and other lesions, requiring extensive work-up and long-term surveillance.
Tethered cord syndrome is a constellation of symptoms and signs that include back and leg pain, bowel and bladder dysfunction, scoliosis and lower extremity weakness and deformity. Tethering may be due to a tight filum terminale or a form of spinal dysraphism. The authors present a case of a 40-year-old man who presented with symptoms of back pain, bilateral lower extremity radicular pain, and bowel and bladder dysfunction. Magnetic resonance imaging showed a sacral lipomyelomeningocele, with fat tracking superiorly to the conus, which was tethered at the L4-L5 level. A minimally-invasive surgical approach with endoscopic visualization and identification of the nerve roots and filum terminale was performed. The patient's postoperative clinical course was uneventful. This case highlights two important issues. First, minimally invasive spine techniques should be considered in the surgical treatment of tethered cord especially given the theoretical advantages of minimizing pain, spinal fluid leakage, and subsequent scarring. And second, endoscopic techniques are advancing. In the case presented here, endoscopic visualization and operative techniques made identification and transection of the filum terminale possible through a tiny dural opening. The small dural opening could theoretically pose the advantage of decreasing the risk of spinal fluid leakage. Clinicians should be aware that endoscopic visualization and techniques can serve as minimally-invasive adjuncts to enhance the traditional approach to many surgical pathologies.
True human tails are rare vestigial structures that are typically removed in childhood. Here a case is presented in which an inconspicuous sacrococcygeal tail was incidentally discovered in late adulthood. A 56-year-old man with no significant past medical history presented to a dermatology clinic with a chief complaint of a hyperpigmented lesion on his central back. However, on full body skin exam, a separate flesh-colored 0.7 cm x 0.5 cm appendage was discovered in the midline sacrococcygeal region. This lesion had been present and unchanged since childhood. This particular lesion was removed via shave biopsy. Microscopic exam found it to be consistent with a diagnosis of a true human tail. There were no apparent involved spinal cord structures, and no further treatment was thought to be necessary. Human tails are congenital anomalies associated with occult spinal lesions in about 50% of cases. Therefore, it is in these patients? best interest to thoroughly evaluate for spinal cord involvement prior to biopsy. There is a relative lack of literature published on the topic, and a greater awareness of human tails would be helpful to ensure their inclusion in a differential diagnosis for persistent sacrococcygeal lesions in patients of any age.
• Two unusual sacrococcygeal neuroepithelial heterotopias manifested as masses associated with cutaneous signs. In a 13-month-old infant, a cystic coccygeal medullary vestige was associated with a midline epidermal nevus. In another patient, a lipomeningocele with neuroepithelial heterotopia manifested as a skin tag and mass in the right buttock. In both cases, the malformations probably resulted from abnormal canalization and retrograde differentiation of the distal neural tube. Cystic coccygeal medullary vestige results from dilation of a persistent ependymal cyst present commonly in neonates at the distal part of the coccyx. The lipomeningocele appears to have arisen from an aberrantly formed ependymal canal. The embryologic events that gave rise to the lesions, the differential diagnosis of postrectal masses, and the common association of midline lesions of skin and soft tissue with neural defects are stressed.
(Arch Dermatol 1982;118:643-648)
The human tail is a relatively rare anatomical curiosity. Once a subject of controversy concerning its evolutionary import,1 it remains an intriguing developmental anomaly today. The main clinical importance lies in the distinction of a human tail from more significant sacrococcygeal lesions, such as meningomyelocele, sacrococcygeal glioma, and teratoma. Few cases have been documented after careful histologic study, and it is likely that many of the earlier cases 1 represented these other lesions.In his definitive embryologic study, Harrison postulated that the human tail resulted from persistence of the vestigial tail, usually the nonvertebral portion (caudal filament), of the 14-16 mm. embryo.2 It is probable that no tails containing an increased number of coccygeal vertebrae, representing Bartel's "true atavistic tail,"3 have been reported. This case represents the second human tail recorded in the American literature since 1929.4Report of a Case
The patient was a Caucasian
Nonterminal myelocystocele is a rare type of spinal dysraphism characterized by a closed defect with an underlying CSF-filled cyst, either contiguous with the central spinal canal or attached to the spinal cord by a fibrovascular stalk. The authors report the unusual case of a neonate with a prenatal diagnosis of cervicothoracic nonterminal myelocystocele who underwent postnatal surgical untethering of the lesion. Pathological analysis of the excised lesion revealed neuroglial tissue with an ependymal lining associated with a mature teratoma. Three months after surgery, the patient has normal lower-extremity sensorimotor function and no evidence of bowel or bladder dysfunction. To the best of the authors' knowledge, this is the first report of a patient with a nonterminal myelocystocele found to have an associated mature teratoma.
Limited dorsal myeloschisis (LDM) is a distinctive form of spinal dysraphism characterized by two constant features: a focal "closed" midline skin defect and a fibroneural stalk that links the skin lesion to the underlying cord. The embryogenesis is hypothesized to be incomplete disjunction between cutaneous and neural ectoderms, thus preventing complete midline skin closure and allowing persistence of a physical link (fibroneural stalk) between the disjunction site and the dorsal neural tube.
We utilize the experience gained from the management of 63 patients with LDM to illustrate these features.
All patients were studied with MRI or CT myelogram, operated on, and followed for a mean of 9.4 years.
There were 11 cervical, 16 thoracic, 8 thoracolumbar, and 28 lumbar lesions. Two main types of skin lesion were: saccular (26 patients; consisting of a skin base cerebrospinal fluid sac topped with squamous epithelial dome or a thin membranous sac) and nonsaccular (37 patients; with a flat or sunken squamous epithelial crater or pit). The internal structure of a saccular LDM could be a basal neural nodule, a stalk that inserts on the dome, or a segmental myelocystocoele. In nonsaccular LDMs, the fibroneural stalk has variable thickness and complexity. All fibroneural stalks contain glioneuronal tissues accompanied by variable quantities of nerves and mesodermal derivatives. In all LDMs, the fibroneural stalk was tethering the cord. Twenty-nine patients had neurological deficits. There was a positive correlation between neurological grade and age suggesting progression with chronicity. Treatment consisted of detaching the stalk from the cord. Most patients improved or remained stable. LDMs were associated with three other dysraphic malformations in more than coincidental frequencies: six LDMs were contiguous with dorsal lipomas, four LDMs shared the same tract or traveled in parallel with a dermal sinus tract, and seven LDMs were related to a split cord malformation. The embryogenetic implications of these associations are discussed.
LDM is a distinctive clinicopathological entity and a tethering lesion with characteristic external and internal features. We propose a new classification incorporating both saccular and flat lesions.
We present a case with spinal myolipoma that was unique in its anatomical composition and symptomatology.
An 18-year-old male presented with urinary retention and buttock pain exacerbated by standing on tiptoe underwent untethering of the low-set conus associated with a sacral fatty tract. Electrical stimulation of the spinal roots beside the upper conus induced anomalous caudal movement of the conus and contraction of the gastrocnemius muscle. In the lower conus, an ectopic muscle bridging the conus and dura was found, and the tissue contracted upon electrical stimulation. The histopathological diagnosis was myolipoma involving mature striated muscle and fat cells. Postoperatively his buttock pain was relieved immediately, but urinary retention persisted.
We posit that his buttock pain, exacerbated by standing on tiptoe, was due to traction of the conus by contraction of the ectopic muscle that was aberrantly innervated from the sacral spinal roots.
Sacrococcygeal teratomas may arise in association with regional developmental errors affecting the caudal embryonic segments and may originate within lumbosacral lipomas. It is therefore possible that sacrococcygeal teratomas and lumbosacral lipomas represent related disorders of embryogenesis. Accordingly, the authors report the cases of 2 siblings. The first child (female) was born with a mature Altman Type III sacrococcygeal teratoma that was resected when she was a neonate. Subsequently, a younger brother was found soon after birth to have an L-4-level lipomyelomeningocele and underwent partial resection and spinal cord untethering at 4 months of age. Although familial forms of each of these conditions have been reported, this is, to the authors' knowledge, the first reported occurrence of lipomyelomeningocele and sacrococcygeal teratoma in siblings. They propose that an inherited regional tendency to developmental error affecting the caudal embryonic segments was shared by these siblings and resulted in spinal teratoma formation in one of them.
Dorsal cutaneous appendages, sometimes referred to as "human tails," are considered to be markers of underlying occult spinal dysraphism. Rarely, these tail-like structures can themselves be the cause of tethered cord syndrome. However, to date, a "bony human tail" causing tethered cord has not been reported in the literature. One such rare lesion is being reported.
A 2-days-old female child was brought for neurosurgical consultation with a skin-covered bony protuberance in the lower back. Examination of the child did not reveal any neurological deficits. Plain radiographic and CT evaluation showed a dorsal bony protuberance arising from the posterior elements of L1 vertebra. MRI showed the cord to be displaced posteriorly and adherent to the undersurface of the bony tail through a lipoma. During surgery, the bony "tail" was excised, and the cord was untethered with excision of the lipoma, which was tethering the cord to the bony "tail." When examined 1 year later, the child was developing normally without any focal neurological deficits.
This case is being reported for its rarity and to highlight the hitherto unreported occurrence of "bony human tail" causing tethered cord syndrome.
Neural tube defects are severe congenital malformations affecting around one in every 1000 pregnancies. An innovation in clinical management has come from the finding that closure of open spina bifida lesions in utero can diminish neurological dysfunction in children. Primary prevention with folic acid has been enhanced through introduction of mandatory food fortification in some countries, although not yet in the UK. Genetic predisposition accounts for most of the risk of neural tube defects, and genes that regulate folate one-carbon metabolism and planar cell polarity have been strongly implicated. The sequence of human neural tube closure events remains controversial, but studies of mouse models of neural tube defects show that anencephaly, open spina bifida, and craniorachischisis result from failure of primary neurulation, whereas skin-covered spinal dysraphism results from defective secondary neurulation. Other malformations, such as encephalocele, are likely to be postneurulation disorders.
There are several human atavisms that reflect our common genetic heritage with other mammals. One of the most striking is the existence of the rare 'true human tail'. It is a rare event with fewer than 40 cases reported in the literature. The authors report a case of an infant born with the true tail. A 3-month-old baby girl, presented with an 11 cm long tail, which was successfully surgically removed. Human embryos normally have a prenatal tail, which disappears in the course of embryogenesis by programmed cell death. Recent advances in genetic research reveal that 'of those organs lost, in evolution, most species carry 'genetic blue prints'. Thus, rarely the appearance of ancient organs like tail may be the result of re-expression of these switched off gene.
The structural complexity of terminal myelocystocele (TMC) precludes a recognizable link to spinal cord development and therefore a plausible embryogenetic theory.
To demystify TMC using clinical, imaging, surgical, electrophysiological, and histopathological data and to propose a theory of embryogenesis.
Our series consisted of 4 newborns and 6 older children. All had preoperative magnetic resonance imagings and surgical repair of the myelocystocele with electrophysiological monitoring.
TMC can be deconstructed into essential and nonessential features. Essential features are present in all TMCs and constitute the core malformation, comprising an elongated spinal cord extending extraspinally into a cerebrospinal fluid--filled cyst that is broadly adherent to the subcutaneous fat. The functional conus resides in the proximal cyst or within the intraspinal cord, and the caudal myelocystocele wall is nonfunctional fibroneural tissue. Nonessential features include variable measures of hydromyelia, caudal meningocele, and fat, present in only some patients. The core structure of TMC strikingly resembles a transitory stage of late secondary neurulation in chicks in which the cerebrospinal fluid-filled bleblike distal neural tube bulges dorsally to fuse with the surface ectoderm, before focal apoptosis detaches it from the surface and undertakes its final dissolution. We theorize that TMC results from a time-specific paralysis of apoptosis just before the dehiscence of the cystic distal cord from the future skin, thereby preserving the embryonic state.
Besides tethering, the myelocystocele may show early rapid expansion causing precipitous deterioration. We recommend early repair with resection of the nonfunctional caudal cyst wall, reconstruction of the proximal neural placode, and duraplasty.
Formation of the caudal spinal cord in vertebrates is by secondary neurulation, which begins with mesenchyme-epithelium transformation within a pluripotential blastema called the tail bud or caudal cell mass, from thence initiating an event sequence proceeding from the condensation of mesenchyme into a solid medullary cord, intrachordal lumen formation, to eventual partial degeneration of the cavitatory medullary cord until, in human and tailless mammals, only the conus and filum remain.
We describe a secondary neurulation malformation probably representing an undegenerated medullary cord that causes tethered cord symptoms.
We present 7 patients with a robust elongated neural structure continuous from the conus and extending to the dural cul-de-sac, complete with issuing nerve roots, which, except in 2 infants, produced neurological deficits by tethering.
Intraoperative motor root and direct cord stimulation indicated that a large portion of this stout neural structure was "redundant" nonfunctional spinal cord below the true conus. Histopathology of the redundant cord resected at surgery showed a glioneuronal core with ependyma-lined lumen, nerve roots, and dorsal root ganglia, corroborating the picture of a blighted spinal cord.
We propose that these redundant spinal cords are portions of the medullary cord normally destined to regress but are here retained because of late arrest of secondary neurulation before the degenerative phase. Because programmed cell death almost certainly plays a central role during degeneration, defective apoptosis may be the underlying mechanism.
A human tail is a rare congenital anomaly with a prominent lesion from the lumbosacro-coccygeal region. It is usually classified either as a true tail or as a pseudo-tail. All the lumbosacro-coccygeal protrusions without the evidence of mesenchymal tissue are classified as pseudo-tail. The association of this rare vestigial entity along with meningomyelocele is rarer still.
Prehensile-tailed platyrrhines (atelines and Cebus) and procyonids (Potos) display bony tail features that have been functionally and adaptively linked to their prehensile behaviors, particularly the need to resist relatively greater bending and torsional stresses associated with supporting their body weight during suspensory postures. We compared fiber architecture of the mm. intertransversarii caudae (ITC), the prime tail lateral flexors/rotators, in 40 individuals distributed across 8 platyrrhine and 2 procyonid genera, divided into one of two groups: prehensile or nonprehensile. We tested the hypothesis that prehensile-tailed taxa exhibit relatively greater physiologic cross-sectional areas (PCSAs) to maintain tail suspensory postures for extended periods. As an architectural trade-off of maximizing force, we also predicted prehensile-tailed taxa would exhibit relatively shorter, more pinnate fibers, and a lower mass to tetanic tension ratio (Mass/P(O)). Prehensile-tailed taxa have relatively higher PCSAs in all tail regions, indicating their capacity to generate relatively greater maximum muscle forces compared to nonprehensile-tailed taxa. Contrary to our predictions, there are no group differences in pinnation angles, fiber lengths or M/P(O) ratios. Therefore, the relatively greater prehensile PCSAs are driven largely by relative increase in muscle mass. These findings suggest that relatively greater ITC PCSAs can be functionally linked to the need for prehensile-tailed taxa to suspend and support their body weight during arboreal behaviors. Moreover, maximizing ITC force production may not come at the expense of muscle excursion/contraction velocity. One advantage of this architectural configuration is it facilitates suspension of the body while simultaneously maximizing tail contact with the substrate.
To report this author's experience with patients with a congenital spinal lipomatous malformation with special emphasis on variations in clinical presentation, operative findings, and outcome based on the classification scheme proposed in the first part of this two part article.
From January 1995 to July 2005, 80 patients with a congenital spinal lipomatous malformation were treated. All patients underwent routine neurological examination, plain radiographs of the spine and all but 10 patients underwent MRI. Ten patients underwent CT-myelography. Hoffman's functional grading scale was used for preoperative and postoperative clinical assessment. The operative findings, complications and outcome were assessed.
Age ranged from 18 days to 19 years. The female: male ratio was 3:2. The malformations were divided into two groups: Group I: Lipomas without a dural defect and, Group II: Lipomas with a dural defect. Included in Group I were: 22 patients out of which there were Caudal lipomas: 10, Filum lipomas:11 and intramedullary lipoma: 1. In Group II there were 58 patients out of which there were Dorsal lipomas: 8, Caudal lipomas with dural defect: 8, Transitional lipomas: 10, lipomyelomeningoceles:28, lipomyeloceles: 4. Most of the group I patients were >5 years of age; cutaneous markers were absent in 60%, older children more often presented with sphincter disturbances. Surgery in group I was straight forward and consisted of sectioning of the filum in filum lipomas, debulking and untethering in caudal lipomas. Duroplasty was seldom required. CSF leak was rare. No patient deteriorated following surgery and no retethering was noted during follow-up. In Group II, all patients had cutaneous markers, most were <2 years of age, 19 were asymptomatic, older children had more severe neurological deficits. Duroplasty was required in most cases. A CSF leak occurred in 12%. Two patients deteriorated temporarily following surgery. Two patients presented with retethering 4 and 8 years after initial surgery. Improvement of more than one Hoffman's functional grade occurred when surgery was done <2 years of age.
Congenital spinal lipomatous malformations do not constitute a single homogenous entity. They can be broadly classified into two groups depending on the presence or absence of a dural defect. These two groups are different from one another embryologically, clinically, surgically and prognostically.