Endodermal Cyst Arising from the Oculomotor Nerve: A Case Report Outlining the Novel Insertion of Cysto-subarachnoid Shunt for Refractory Disease

Pediatric intracranial neurenteric cyst of the oculomotor nerve: a case-based review

BACKGROUND

Neurenteric cysts (NECs) of the central nervous system (CNS) are uncommon congenital entities arising from embryonal elements. Intracranial NECs in the pediatric population are rare.

METHODS

The authors describe the presentation, radiographic imaging, and pathologic findings of an 11-year-old boy with a right oculomotor nerve NEC. A literature review was performed to identify additional cases of pediatric intracranial NECs published in the English language, over the past 30 years (1990-2020). The authors discuss the presentation, investigations, management, and prognosis of this interesting entity.

RESULTS

We describe an 11-year-old boy who presented to neurosurgical attention with disconjugate gaze, anisocoria, and ptosis. Magnetic resonance imaging (MRI) demonstrated a lobulated, cystic, and peripherally enhancing mass involving the right oculomotor nerve. The patient underwent pterional craniotomy for drainage of the cyst and subtotal resection of the cyst wall. The tan-colored mass was displacing the basilar artery, compressing the cerebral peduncle, and adherent to the inferior surface of the tentorium. The lesion was within the oculomotor nerve and splitting the fibers, and the cystic contents were thick and mucinous. Histopathological examination of the specimen demonstrated a thin fibrous cyst wall with scattered inflammatory cells and lined by simple columnar epithelium containing mucin. The lining cells were immunoreactive with epithelial membrane antigen (EMA) and pan-keratin AE1/AE3. The diagnosis of a NEC was rendered. A comprehensive literature review of pediatric intracranial NECs yielded 46 additional lesions published in the literature, involving the skull base, posterior fossa, cerebral convexity, and cranial nerves. NECs present with local mass effect and less commonly, with aseptic meningitis or intracystic hemorrhage. Maximal safe GTR remains the mainstay management, although cyst drainage and marsupialization, cyst shunting, and fenestration of cystic contents into the ventricle or basal cisterns have been reported with variable success.

CONCLUSION

CNS NECs are rare congenital entities; although they occur less frequently in the intracranial components compared to the spine, their diagnosis and management should be considered for intracranial cystic lesions. Maximal safe GTR is the mainstay treatment and frequently yields favorable outcomes.

Symptomatic Oculomotor Nerve Cyst in a 3-Year-Old Child: Case Report With Emphasis on Surgical Management

BACKGROUND AND IMPORTANCE

Third nerve palsies in the pediatric population are most commonly caused by trauma, tumors, or vascular abnormalities. Cystic oculomotor nerve neuropathies, however, are rare. We report the case of a symptomatic cyst along and within the oculomotor nerve, which has not been described previously.

CLINICAL PRESENTATION

Here, we report a case of a 3-yr-old girl presenting with a progressive painless oculomotor nerve palsy. A magnetic resonance imaging revealed a cystic formation along the cisternal and cavernous course of the nerve. Due to lack of alternative treatment options, surgery was offered. Intraoperative direct nerve stimulation allowed for identification of a non-functional part of the cyst wall and open fenestration and biopsy were executed. Histopathology revealed neuritis. Serology was negative for various pathogens. The oculomotor palsy rapidly resolved. At a follow-up 5 yr after surgery, the girl is asymptomatic and the cisternal part of the cyst remains collapsed.

CONCLUSION

This is the first report of a symptomatic cyst along and within the oculomotor nerve treated effectively with open fenestration and decompression highlighting the importance of intraoperative neuromonitoring in cranial nerve surgery. Uncertainty remains regarding the etiology of this disease.