Challenging, Giant Occipital Encephalocele in a Pediatric Saiponese Male

Abstract

Key Clinical Message
Giant occipital encephalocele is a rare form of congenital anomaly that involves protrusion of brain tissue (greater in size than the patient's cranial cavity) from a defect in the skull. This case reports illustrates repair of a giant encephalocele and emphasizes important methods to reduce risk for blood loss and other complications.

Abstract
A rare form of congenital anomaly, giant occipital encephalocele involves protrusion of brain tissue from a defect in the skull (in this case from the occiput). While encephalocele itself is a fairly rare entity, those qualifying as “giant”—defined by size of the deformity exceeding that of the skull itself – require very technically challenging surgery.

Full text

Clin Case Rep. 2023;11:e7380.
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https://doi.org/10.1002/ccr3.7380
wileyonlinelibrary.com/journal/ccr3
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INTRODUCTION
An encephalocele is a type of cranial dysraphism charac-
terized by herniation of intracranial contents including
meninges, brain, blood vessels, and ventricular compo-
nents through a midline calvarial defect.1 As a rare form
of neural tube defect, their etiology involves defective
embryogenesis that can occur spontaneously or in asso-
ciation with early gestational exposures including hy-
perthermia, radiation, salicylates, and viral infection.2
The giant variant, deemed as such when the encephalo-
cele sac is larger than the newborn's head, represents a
particularly rare and formidable treatment challenge in
neurological surgery.3,4 These challenges arise from the
relatively small circulating blood volume of the newborn
patient coupled with resection of the often highly vascular
encephalocele, which potentiates the risk of blood loss,
hypovolemia, hypothermia, coagulopathy, and electrolyte
imbalance from large fluid shifts in addition to unique
anesthetic and airway concerns.2,5 Large encephaloceles
can be surgically treated with either truncation of the dys-
plastic neural tissue or reinternalization of the tissue into
the cranial vault.6 Reinternalization in the giant variant
poses a significant challenge due to the exceptionally high
volume of tissue involved. Groups seeking to reinternalize
the dysplastic tissue in these cases have reported perform-
ing concomitant cranial vault expansion to accommodate
this volume and to avoid mass effect on the adjacent brain
and intracranial hypertension.7 Because there is unclear
benefit and possible detriment to reinternalization of the
dysplastic neural tissue— and it can necessitate a more
complex operation with higher risk— it is our practice to
truncate the encephalocele tissue in large or giant lesions.
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CASE ILLUSTRATION
We present a newborn Saipanese male with limited pre-
natal care who presented to our institution with a giant
occipital encephalocele with intact overlying dermis and
Received: 26 December 2022
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Revised: 1 April 2023
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Accepted: 3 May 2023
DOI: 10.1002/ccr3.7380
CASE REPORT
Challenging, giant occipital encephalocele in a pediatric
saipanese male
JoshuaLoya
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Nolan J.Brown
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DavidGonda
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MichaelLevy
This is an open access article under the terms of the Creative Commons Attribution-NonCommercial-NoDerivs License, which permits use and distribution in any
medium, provided the original work is properly cited, the use is non-commercial and no modifications or adaptations are made.
© 2023 The Authors. Clinical Case Reports published by John Wiley & Sons Ltd.
Department of Neurosurgery,
University of California San Diego,
Rady's Children's Hospital, San Diego,
California, USA
Correspondence
Nolan J. Brown, Department of
Neurosurgery, University of California
San Diego, 200 W Arbor Dr., #MC7893,
San Diego, CA 92103, USA.
Email: nolanb@uci.edu
Key Clinical Message: Giant occipital encephalocele is a rare form of congenital
anomaly that involves protrusion of brain tissue (greater in size than the patient's
cranial cavity) from a defect in the skull. This case reports illustrates repair of a
giant encephalocele and emphasizes important methods to reduce risk for blood
loss and other complications.
Abstract: A rare form of congenital anomaly, giant occipital encephalocele in-
volves protrusion of brain tissue from a defect in the skull (in this case from the
occiput). While encephalocele itself is a fairly rare entity, those qualifying as
“giant”— defined by size of the deformity exceeding that of the skull itself – re-
quire very technically challenging surgery.
KEYWORDS
congenital malformation, dysraphism, encephalocele, neural tube defect, pediatric

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pedunculated base (Figure1). On examination, the pa-
tient elicited a strong cry with good facial symmetry and
suckle, tolerated oral feeds, moved all extremities sponta-
neously with gross symmetry, and had a full but soft fon-
tanel. An MRI was obtained showed a giant encephalocele
sac containing a large amount of dysplastic brain tissue
and ventricular components with a robust vascular supply
as demonstrated on MR venogram (Figures2 and 3). As
noted by Zhahid and Khizar,8 the meningeal membrane
that surrounds the giant encephalocele can be covered
by a normal membrane, one that is unusually thin, or
alternatively a dysplastic (abnormal) membrane, as was
the case with our patient. The “large amount of dysplas-
tic brain tissue” evident on MRI is therefore a reference
to the large amount of abnormal tissue surrounding the
brain that will eventually require dissection and removal.
As this patient was certainly a candidate for surgical in-
tervention, discussion was had with the parents regarding
the profound neurocognitive disability often associated
with these severe malformations and the decision was
made to proceed with maximal surgical care after coun-
seling. After fiberoptic intubation the patient was placed
prone in a horseshoe headrest taking care to support the
encephalocele manually during positioning, prepping,
and draping to avoid tearing or rupture. A circumferen-
tial incision is made just below the equator of the lesion
and dissection is carried anteriorly and circumferentially
toward the calvarial defect being careful to remain in the
dysplatic subcutaneous plane outside the neural tissue to
minimize blood loss. Once the root of the encephalocele
with its vascular supply is isolated around a perimeter,
it is ligated with heavy silk suture at the base (Figure4).
Given the size of the encephalocele, it was determined
that attempting to internalize the encephalocele material
into the calvarium could place the native and ostensibly
more normal neural structures at risk. Therefore, the en-
cephalocele was truncated at its pedunculated base which
appeared highly vascular and disorganized. The dysplatic
tissue was then resected leaving a ligated end which is
internalized and covered with native dura that was freed
surrounding the defect (Figure5). The patient remained
hemodynamically stable during the perioperative and
postoperative course and was extubated. Following the
encephalocele repair, head circumference and transfonta-
nelle ultrasound results were tracked on a daily basis. This
demonstrated increasing head circumference through
growth curves and increasing ventricular size consistent
with hydrocephalus. As a result, the decision was made
to place a cerebrospinal fluid shunt in delayed fashion
for unresolved hydrocephalus. At the time the shunt was
FIGURE  Newborn Saipanese male with limited prenatal care
born at full term with an occipital mass.
FIGURE  Magnetic resonance imaging revealed a 1.4 cm
calvarial defect with a giant occipital encephalocele containing a
large amount of dysplastic brain tissue.
FIGURE  Magnetic resonance venogram shows robust
vascular bundle supplying the dysplastic brain tissue within the
encephalocele.

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placed (within 3 weeks postoperative) there were no signs
of CSF leak, visual acuity deficits, or wound infection. Of
note, hydrocephalus is commonly reported in conjunction
with giant encephaloceles. As such, it was not thought to
be a complication of the surgical intervention or the result
of bleeding or other iatrogenic cause, but rather a feature
related to the natural history and constellation of pathol-
ogy associated with occipital encephaloceles.
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DISCUSSION
Numerous factors affect the outcome of surgical inter-
vention in patients with encephaloceles, with the occiput
being the most common location for this class of cranial
dysraphisms. Among these factors include location, the
size of the sac, the amount of brain matter herniated into
the contents of the sac, the presence versus absence of the
brainstem, occipital lobe, and dural sinuses within the
sac, and whether or not hydrocephalus is present.8 Even
in cases where the surgeon is well aware of these factors
and fully equipped to address them, complications such as
intraoperative blood loss and perioperative hypothermia
are in some cases inevitable and the potential for their oc-
currence lends an added layer of complexity to these cases.
Even more complex and challenging are giant occip-
ital encephaloceles, an extremely rare, formidable form
of encephalocele that can be very challenging for neu-
rosurgeons to treat successfully. Also referred to as large
or massive encephaloceles, giant encephaloceles are re-
ported in only a few cases in reports in the literature and
their exact incidence is unknown. Typically, patients with
giant occipital encephaloceles will present as neonates
and infants due to difficulties nursing and feeding, even
when their defect should be recognized and addressed
at birth.4 When the patients eventually present weeks or
even months down the line, microcephaly, cleft lip, and
CSF leak may be observed.4
Preoperatively, MRI should be evaluated to assess the
condition of the transverse sinus and torcula in giant oc-
cipital encephaloceles, as these sinuses can herniate with
other contents into the sac. MRI is also the first choice of
imaging because CT should only be performed as a last re-
sort due to risks of infant exposure to radiation (sometimes
CT may be necessary to assess the structural integrity of
the underlying bone). In a recent cases series of 14 chil-
dren with giant encephaloceles (13 of which were located
occipitally), hydrocephalus was present in 10 patients
upon presentation.4 Seven of these patients ultimately re-
quired ventriculoperitoneal (VP) shunt, of which five were
placed during the encephalocele repair surgery and the re-
maining two were inserted postoperatively in the setting of
worsening hydrocephalus, the same scenario that required
postoperative shunt insertion in our patient.4
Intraoperatively, perhaps the most challenging decision
the surgeon will face is whether to perform partial exci-
sion of the brain or return its contents in full back into
the intracranial cavity. In an ideal situation, all brain tis-
sue would of course be kept, but the challenge of doing so
in these anomalous cases is that the volume of herniated
brain exceeds the size of cranial vault and cavity. In the
series reported by Mahapatra and colleagues, 7/14 patients
underwent partial excision of brain prior to closure.4 Other
measures can be taken to avoid concerning elevations in
ICP even when the full brain contents are returned—
these include expansile cranioplasty and craniectomy—
however, these measures involve a delicate balance of
many considerations as even small fluctuations in ICP in
infants can lead to complications such as sudden cardiore-
spiratory arrest.4 In sum, this surgery should be completed
FIGURE  The pedicle of the dysplastic brain tissue is ligated
with suture after circumferential dissection approaching the
calvarial defect.
FIGURE  The remnant ligated pedicle and surrounding
dysplastic dura and dermal tissue at the cranial defect after
resection of the encephalocele contents.

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in an efficient manner as possible due to risks for infant
hypothermia, complications resulting from prolonged ad-
ministration of anesthesia, blood loss, infection, respira-
tory distress, and aspiration pneumonia, among others.
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CONCLUSIONS
Herein, we present the rare case of a newborn Saiponese
male with giant occipital encephalocele that was surgically
reduced back into the patient's intracranial cavity during
an exceedingly complex and risky procedure. Fortunately,
the surgery was successful and the patient made good re-
covery in the immediate postoperative course. When en-
countered, all encephaloceles— including those meeting
the criteria for “giant” and located occipitally— should
be evaluated for the following, as these are the most im-
portant factors informing operative plan: encephalocele
location, size, contents, and presence versus absence of
hydrocephalus.
AUTHOR CONTRIBUTIONS
Joshua Loya: Conceptualization; investigation; meth-
odology; project administration; supervision; validation;
visualization; writing – original draft; writing – review and
editing. Nolan J. Brown: Writing – original draft; writing
– review and editing. David Gonda: Conceptualization;
project administration; supervision; validation; visu-
alization; writing – review and editing. Michael Levy:
Conceptualization; supervision; validation; writing – re-
view and editing.
FUNDING INFORMATION
Authors report no funding sources related to this work.
CONFLICT OF INTEREST STATEMENT
Authors report no conflicts of interest related to this work.
DATA AVAILABILITY STATEMENT
Data cannot be shared for confidentiality reasons. Queries
about the data should be directed to the corresponding
author.
ETHICS STATEMENT
Ethical approval was not required for this study in accord-
ance with national guidelines.
CONSENT
Written informed consent was obtained from the patient
to publish this report in accordance with the journal's pa-
tient consent policy.
ORCID
Nolan J. Brown https://orcid.org/0000-0002-6025-346X
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How to cite this article: Loya J, Brown NJ,
Gonda D, Levy M. Challenging, giant occipital
encephalocele in a pediatric saipanese male. Clin
Case Rep. 2023;11:e7380. doi:10.1002/ccr3.7380