Enigmatic intracranial cyst causing diplopia and trigeminal neuralgia

Chronic compression by intracranial cystic lesions can cause cranial nerve palsies and bony changes. With the advent of imaging techniques, grossly accurate diagnosis is possible. However, few cases do surprise the clinicians both intra, and postoperatively. A 27-year-old male presented to us with complaints of double vision for 4 months followed by sharp, shooting pain in the left V1 and V2 distribution for 1-month duration, on examination, he had left lateral palsy and decreased pin prick and temperature sensation in V1 distribution. On computed tomography scan, a cystic lesion noted which is isodense in the middle cranial fossa with erosion of the underlying bone. On magnetic resonance imaging lesion was iso to hyperintense on T1-Weighted and hyperintense on T2-Weighted, brilliantly enhancing on contrast administration. Provisional diagnosis was trigeminal schwannoma, left temporal craniotomy and total excision of the cyst done. Histopathological examination showed cyst wall lined with collagen. Postoperatively patient neuralgic pain subsided with persisting sixth nerve palsy.