Primary isolated cerebellopontine angle papillary craniopharyngioma

Mayur Sharma, Rahul Mally, Vernon Velho, Kharosekar Hrushikesh 
 Department of Neurosurgery, Main Hospital Building, Grant Medical College and Sir J.J Group of Hospitals, Byculla, Mumbai, India

Correspondence Address:
Mayur Sharma
Department of Neurosurgery, Main Hospital Building, Grant Medical College and Sir J.J Group of Hospitals, Byculla, Mumbai
India

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Sir,

Craniopharyngiomas are benign slow-growing tumors and occur most commonly in the suprasellar location. These tumors are supposed to arise from the remnants of the Rathke's pouch epithelium. There are two histologic variants: adamantinomatous and papillary. [1] We report a rare case of right cerebellopontine angle papillary craniopharyngiomas without suprasellar component.

A 26-year-old housewife presented with headache of 3 months duration. The patient had a history of head injury due to fall from motorbike 6 months earlier. Neurologic examination revealed visual acuity 6/9 in right eye and 6/18 in left eye and no other deficits. Cranial computed tomography (CT) scan showed a hyperdense extra- axial lesion in right cerebellopontine angle suggestive of acute extradural bleed causing compression of brainstem, cerebellum, and fourth ventricle. Magnetic resonance imaging (MRI) [Figure 1] was suggestive of a well-defined extra-axial lesion in right cerebellopontine angle, which was hypointense on T1-, T2-weighted, and FLAIR images. The lesion was not enhancing on contrast and there was no restriction on diffusion-weighted images, suggestive of extradural hematoma. The patient was operated with right retromastoid suboccipital craniectomy. A well-defined greenish cystic lesion could be seen and around 20mL of greenish jelly-like fluid was aspirated. The cyst wall was thin and loosely attached to the surrounding neurovascular structures. The cyst wall was completely excised. There was no neurologic deficit postoperatively. Postoperative CT scan [Figure 2] showed complete excision of the lesion. Neuropathology [Figure 3] was showing monomorphous mass of immature squamous epithelium lining the cyst wall along with wet keratin, which was suggestive of papillary craniopharyngioma. Our patient has not shown any recurrence at the recent follow-up at 6 months.{Figure 1}{Figure 2}{Figure 3}

Craniopharyngiomas rarely can extend into the posterior fossa in 4%-5.9% of all craniopharyngiomas. [2] Very rarely these tumors can arise in the cerebellopontine angle without suprasellar component. [3] These tumors have bimodal age distribution with first peak at 5-15 years and second peak at more than 60 years. There are two main hypotheses regarding the origin of ectopic craniopharyngiomas, first, the ectopic squamous epithelial remnants from the craniopharyngeal canal may migrate into the posterior fossa. Second, these ectopic squamous cells may develop into ectopic craniopharyngiomas. [4] The ability of craniopharyngiomas to migrate along the cerebrospinal fluid spaces and resection tracts has been well documented. [5] Both CT scans and MRI scans are the preferred modality for the diagnosis. [6] Surgical excision of the tumor is the treatment of choice. However, adherence of the wall to important structures, such as vessels, cranial nerves, or infiltration into the brain stem cerebellum makes complete removal challenging. [7] This case highlights a rare possibility of occurrence of this common tumor at uncommon location.

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