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Neuromuscular choristoma (original resection specimen). Some nerve fiber bundles appeared to contain individual skeletal muscle fibers (hematoxylin and eosin, X250).
Source publication
Neuromuscular choristomas are rare, with only 13 cases having been previously reported. They usually arise in association with large nerves, and most often occur in the first decade of life. A few have been congenital. Although resection is typically curative, in two instances partial resection alone appears to have been followed by spontaneous reg...
Context in source publication
Context 1
... variable orientation, although many were strap-shaped and disposed in parallel ar- ray. Nerve fibers were often arranged in loose fascicles or small groups surrounding clusters of skeletal muscle cells, an arrange- ment most conspicuous at the periphery of lesion. At high mag- nification, some fascicles were actually seen to contain myo- cytes (Fig. 2). The nerve fiber-muscle relationship was highlighted by the Bielschowski reaction for axons (Fig. 3) as well as by immunostains for S-100 protein that demonstrated Schwann sheaths. Myelin was not noted on LFB-PAS stain. Similarly, stains for EMA, performed to determine whether perineural cells were present, were negative. No immature ...
Citations
... Histologisch findet sich Skelettmuskulatur in den myelinisierten Nervenfasern [298]. Aufgrund der wenigen publizierten Fälle können keine adäquaten Therapiemaßnahmen empfohlen werden. ...
Die biologische Heterogenität und die in den letzten Jahren weiterentwickelten Möglichkeiten
in der Diagnostik (Neurosonographie, Kernspintomographie, Molekularpathologie und
genetische Diagnostik) und Therapie (intraoperatives Neuromonitoring, intraoperative
Neurosonographie) lässt eine große Variationsbreite in der Versorgungsqualität von PNT
erwarten.
Diese Leitlinie versucht, bekannte und neue Verfahren in Diagnostik und Therapie zu bewerten
und stützt sich auf die wissenschaftliche Literatur und die Expertise ausgewiesener
Spezialisten aus den verschiedenen, an der Behandlung der Tumoren beteiligten
Fachrichtungen. Ziel ist es, verlässliche und allgemein akzeptierte Definitionen des
Notwendigen und Angemessenen in Diagnostik und Therapie zu geben.
Die Diagnostik der peripheren Nerventumoren findet primär im ambulanten/ vertragsärzlichen
Bereich statt. Die Behandlung kann in Einzelfällen ambulant, muss jedoch bei einer Vielzahl
tiefsitzender und komplexer PNT stationär erfolgen. Den Leitlinienentwicklern ist bewusst,
dass die Versorgung durch Vertreter unterschiedlicher Fachdisziplinen erfolgt.
Diese Leitlinie soll Entscheidungen in der Diagnostik und medizinischen Versorgung von
Patienten mit PNT-verdächtigen Symptomen auf eine rationale Basis stellen und die Qualität
der Versorgung verbessern.
... The classic microscopic composition is of skeletal muscle and nerve fibers only, but smooth muscle components have rarely been described (2). In its usual form, NMC arise from a major nerve or nerve trunk, usually during the first decade of life (3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15)(16)(17)(18)(19). Typically, there are signs of neurological impairment including atrophy, palsy/paresthesias, or contractures, with or without an associated mass (3-10, 12, 14-16, 18, 19). ...
... There are a few papers reporting the association between NMC and desmoid fibromatosis (DF) (5,7,9,16,20,21). In the published cases, the development of DF usually occurred after a surgical procedure for the diagnosis or treatment of a neural lesion (9,16,20). ...
... There are a few papers reporting the association between NMC and desmoid fibromatosis (DF) (5,7,9,16,20,21). In the published cases, the development of DF usually occurred after a surgical procedure for the diagnosis or treatment of a neural lesion (9,16,20). For this reason, some authors profess a "no-touch" approach if an NMC is clinically suspected of a nerve lesion (21). ...
Neuromuscular choristoma (NMC) are lesions of the peripheral nervous system characterized by an admixture of skeletal muscle fibers and nerves fascicles that are frequently associated with desmoid fibromatosis (DF). Mutations in CTNNB1, the gene for β-catenin protein, are common in DF and related to its pathogenesis. They are restricted to exon 3, with 3 point mutations: T41A, S45F, and S45P. To understand the pathogenesis of NMC, we tested CTNNB1 status in 5 cases of NMC whether or not they were associated with DF. The screening of mutations in CTNNB1 gene was based on amplicon deep sequencing using the ION Proton platform. Three patients had the S45F mutation; in 2 the mutation was common to both lesions and in one the DF was wild type while the NMC had the S45F mutation. One patient had a T41A mutation in the NMC and no associated DF. In the last patient, the DF lesion had a T41A mutation; there was no lesion with the S45P mutation. The presence of similar CTNNB1 mutations in NMC/DF-associated lesions and sporadic DF reinforces the relationship between both lesions and points to a common pathogenic mechanism.
... N euromuscular choristoma (NMC) is a rare developmental lesion characterized by the presence of mature skeletal muscle within peripheral nerve fascicles. [1][2][3][4][5][6][7][8][9] NMCs typically involve major nerves or plexuses, and patients typically present with neuropathic symptoms or chronic undergrowth in the affected nerve's territory. 4,10 In our experience, approximately 80% of patients with NMC develop a soft tissue fibromatosis within the ABBREVIATIONS: DTF, desmoid-type fibromatosis; FFPE, formalin-fixed paraffin-embedded; LN, lipomatosis of nerve; MRI, magnetic resonance imaging; NMC , neuromuscular choristoma innervation territory of the NMC-affected nerve segment. ...
... NMC is a developmental malformation of peripheral nerves, most often the sciatic nerve, causing undergrowth in the affected nerve's territory. [1][2][3][4][5][6][7][8][9] In our experience, NMC-DTF develops in approximately 80% of patients with NMC, 20 and invariably arises within the NMC-affected nerve innervation territory. 14 As biopsy of the NMC may trigger or accelerate development of the NMC-DTF, we now rely on clinicoradiological features for both diagnosis and surveillance of NMC. ...
... Similarly, 3 published cases of NMC-DTF arising in association with NMC of the brachial plexus or sciatic nerve recurred multiple times after resection, ultimately resulting in forequarter or lower-limb amputation. 1,3,9,31 These reports predated availability of molecular CTNNB1 testing, and the patients did not receive contemporary treatment protocols. Based on these observations, we now use serial imaging to monitor all patients with NMC for early development of NMC-DTF. ...
BACKGROUND
Neuromuscular choristoma (NMC) is a peripheral nerve malformation frequently associated with a fibromatosis (NMC-DTF) that mimics sporadic desmoid-type fibromatosis (DTF). Sporadic DTF is often managed conservatively but its clinical behavior varies. CTNNB1 mutational subtypes in sporadic DTF have prognostic value. We have previously identified CTNNB1 mutations in NMC, and 3 paired NMC-DTF but the clinical behavior of NMC-DTF is poorly understood.
OBJECTIVE
To evaluate patients with NMC-DTF to determine (1) CTNNB1 mutational subtypes in NMC-DTF, and (2) associated clinical behavior and response to treatment.
METHODS
Retrospective review of clinical, imaging, and pathologic features of patients with NMC and NMC-DTF, and molecular testing for CTNNB1 mutations.
RESULTS
Among 7 patients with NMC of the sciatic nerve (median age: 18 yr), NMC-DTF (mean size 10.7 cm) developed shortly following NMC biopsy (N = 5) or spontaneously (N = 2): 6 NMC-DTF had CTNNB1 p.S45X mutations and 1 NMC-DTF had a p.T41A mutation. All patients with CTNNB1-p.S45-mutated NMC-DTF developed local progression after wide local excision or active surveillance, including one distal metachronous NMC-DTF. No patient had spontaneous disease stabilization. Following adjuvant radiation or systemic therapy, disease stabilization was achieved in 4 (of 6) patients. One patient progressed on sorafenib treatment.
CONCLUSION
NMC-DTF frequently contain CTNNB1 p.S45 mutations, behave aggressively, and require adjuvant therapies for disease stabilization. We now use imaging alone to diagnose NMC, and routinely surveille the NMC-affected nerve segment to identify early NMC-DTF. In contrast to sporadic DTF, earlier adoption of systemic therapeutic strategies may be required for optimal disease management of NMC-DTF.
... Another rare hamartoma of neuromuscular origin, i.e. benign triton tumour was previously reported occurring in the upper lip of young children (Hemalatha et al., 2014). Histopathologically, this tumour exhibits peripheral nerve proliferation with focal skeletal muscle differentiation in an organised architecture (Mitchell et al., 1995). The word 'triton' was coined from Triton salamander, an amphibian with the neural ability to induced skeletal muscle regeneration. ...
... Our literature review revealed 8 potential cases [1,3,4,7,23,27,37,38] of NMC-DTF (based on biopsy, clinical and radiological findings) that were reported by other authors ( Table 3). The mean age at clinical presentation was 6 years (range 0 to 28 years). ...
Introduction:
Desmoid-type fibromatosis (DTF) frequently arises in patients with neuromuscular choristoma (NMC). We hypothesize that NMC-associated DTF occurs in soft tissues innervated by the NMC-affected nerve, and arises from CTNNB1-mutated (myo) fibroblasts within or directly adjacent to the NMC.
Materials and methods:
A retrospective review of patients treated at our institution was performed for patients with biopsy-confirmed diagnosis of NMC-DTF. Clinical presentation, physical examination, electrodiagnostic findings and radiological features (MR and FDG PET/CT images for each NMC-DTF) and pathologic re-review of available materials were analyzed. A literature review was also performed.
Results:
Eight patients from our institution met the inclusion criteria. All patients presented with neuropathic symptoms and soft tissue or bone changes in the nerve territory innervated by the NMC. All MR images (N=8 cases) showed the characteristic features of NMC, and also showed direct contact between unifocal (N=5) or multifocal (N=3) DTF(s) and the NMC-affected nerve NMC. FDG PET/CT (N=2 cases) showed diffuse, increased FDG uptake along the entire affected nerve segment, contiguous with the FDG-avid DTF. In all cases, the DTFs arose in the soft tissues of the NMC-affected nerve's territory. No patient developed DTF at any other anatomic site.
Conclusions:
These data demonstrate that NMC-DTF arises solely within the NMC-affected nerve territory, and has direct contact with the NMC itself. Based on all these findings and the multifocality of NMC in several cases, we recommend imaging and surveillance of the entire NMC-affected nerve (from spine to distal extremity) to identify clinically-occult DTF in patients with NMC.
... Some authors have described discrete lesions arising from the nerve that was resectable without a new neurologic deficit [17]. Other reports range from biopsy only [18][19][20], attempted resection [4], amputation [4,21], while others undertook complete resection of the involved nerve with nerve grafting and assumed postoperative paralysis of the affected limb [16]. ...
... This tumor was first reported in 1895 by Orlandi who described a case involving the sciatic nerve [2]. NMCs are also known as "benign Triton tumors" and this term refers specifically to tumors which derive from neoplastic (typically Schwann) nerve sheath cells that exhibit myogenic differentiation [3]. While the histological origin of NMCs is disputed, one theory suggests that skeletal muscle cells are trapped by nerve cells at the time of embryogenesis [4]. ...
... In our case, skeletal muscle cells were found in conjunction with nerve fibers at a site neural tissue. Furthermore, NMCs typically form fibrous tissue, as was seen on excision, due to degeneration of muscle and nerve cells from lack of stimulation [3]. ...
... They typically present as solitary lesions in childhood with no male/ female preponderance, and have been reported to be associated with cranial nerves or large peripheral nerves such as the brachial plexus, median nerve, and sciatic nerve. [1,2,5,6,[8][9][10][11]13,14] To date, eight cases of sciatic nerve neuromuscular hamartomas have been reported. [2,3,[7][8][9][10]12] This present case represents the ninth. ...
... [2,3,[7][8][9][10]12] A cavovarus foot was described in five of the cases as well. [2,7,9,11,12] While unilateral foot deformity may suggest a spinal etiology such as diastematomyelia or tethered cord, this collection of reports highlights that in rare cases peripheral nerve lesions may produce this clinical sign as well. Most cases of neuromuscular choristoma occur in childhood and typically demonstrate a relatively benign clinical course though the natural history has not been well-understood. ...
... Microscopically these lesions are usually composed of fascicles separated by fibrous tissue, with the neural tissue intimately associated with the skeletal muscle in nerve fibers or small nerves, and may be sharing the same perimysial sheath. [11,13] The benefits achieved by total resection of the lesion must be weighed against the potential neurologic deficit from doing so. In our case, resection of the lesion in the absence of uninvolved nerve would technically necessitate resection and grafting of the sciatic nerve and result in unacceptable neurologic deficit in an ambulatory patient. ...
Neuromuscular hamartomas are rare benign tumors with mature skeletal elements mixed with mature neural elements. They present typically as solitary lesions in childhood and have been reported to be associated with cranial nerves or large peripheral nerves such as the brachial plexus, median nerve, and sciatic nerve. To date, eight cases of sciatic nerve neuromuscular hamartomas have been reported. We present a case along with an outline for the natural history of the disease with a review of the literature of the reported cases dating back to 1895.
An 11-year-old boy presented with progressive right lower extremity pain and atrophy. Magnetic resonance imaging revealed a large right sciatic nerve mass, and electromyography demonstrated evidence of ongoing denervation and reinnervation. Initial computed tomography-guided biopsy was unrevealing and subsequent open biopsy was consistent with neuromuscular choristoma.
Neuromuscular choristomas represent a rare disease. Symptoms of foot deformity, leg size discrepancy, and pain merit a complete work-up including spinal and peripheral nerve etiologies.
... Bonneau et al. [7] discussed a case of a 14-year old girl with multiple small neuromuscular hamartomas surrounding a recurrent massive fibromatosis of the right axilla. Mitchell et al. [8] reported a classic case of neuromuscular hamartoma in a femalepatient where the lesion appeared to grow after incomplete initial resection. Re-excision revealed fibromatosis. ...
Aggressive fibromatosis is a benign but locally-aggressive tumor, which most often affects the muscles of the shoulder, the pelvic girdle, and the thigh. It usually affects adolescents and young adults. Desmoplastic fibroma, considered the bone counterpart of soft tissue fibromatosis, is a rare tumor that usually affects the metaphyseal or diaphyseal portions of long bones or, less commonly, the jaw. Neuromuscular hamartoma, a rare developmental lesion composed of mature elements of both striated muscle and nerve, is usually diagnosed in infants and children and affects large nerve trunks. Rarely, it can affect the head and neck region. Occasional cases showing an association between aggressive fibromatosis and neuromuscular hamartoma have been reported in the literature. Here we present a unique case of an adult patient with desmoplastic fibroma of the mandible in association with neuromuscular hamartoma.
... In most of the earlier case reports, the NMC involved a peripheral nerve, often one of a major nerve trunk. [17][18][19][20][21][22][23] Only 3 of these cases occurred in adults, and all 3 adults had experienced neuromuscular symptoms dating back to childhood or adolescence. 17 Although extracranial NMCs are more common in children, 22 of the 27 cases of intracranial NMCs occurred in adults. ...
... Radiologically, the tumor was reported to be hyperattenuated on unenhanced computed tomography. 29 Two other case reports 22,29 did not describe the imaging characteristics. A subsequent case report 9 described a tumor with low T1 and intermediate T2 characteristics with patchy internal enhancement. ...
... Their theory was supported by the fact that several patients with NMCs experienced multiple recurrences after resection. [17][18][19]22 On the other hand, Louhimo and Rapola 30 reported 2 cases of NMCs that underwent spontaneous regression after biopsy and subtotal resection. They did not include follow-up data that provided information about recurrence of these lesions. ...
Neuromuscular choristomas (NMCs) are rare benign tumors of the peripheral nerves. Although histopathological characteristics of this unusual lesion have been recognized, in this regard, neuroimaging findings have not been well described previously. We report the first intraconally located NMC affecting the oculomotor nerve, with histopathological and radiological characteristics.
A 10-year-old girl presented with sudden-onset left temporal and retro-orbital pain. Magnetic resonance imaging scans demonstrated a small, capsulated, retro-orbital, intraconal solid lesion that was diagnosed as an atypical dermoid cyst preoperatively. The tumor was resected subtotally. Postoperatively, the patient became pain free, but ipsilateral ptosis and upward eye movement failure developed. Histologically, the lesion consisted of well-differentiated striated muscle fibers intermingled with mature nerve elements consistent with the NMC.
Although intracranial NMCs need histological confirmation for diagnosis, neuroimaging might contribute to the preoperative diagnosis and management strategy of treatment. We report the first intraconal NMC, which should be considered in the differential diagnosis of intraorbital tumors.
