NEURORADIOLOGY

A 45 year old male presented with history of severe headaches of 2 years duration. CT scan was done and it showed a well defined, mildly hyperdense, non enhancing lesion in the Foramen of Monro, with obstructive hydrocephalus, this was reported as a colloid cyst. Bilateral ventriculo-peritoneal shunts were introduced, and subsequent scan showed regression of the hydrocephalus.
A year later, patient developed a progressive loss of memory; an MRI scan of the brain was performed.
What is your diagnosis ?

Diagnosis : Intra ventricular craniopharyngioma

MRI shows a well defined, hyperintense lesion entirely within the third ventricle on both the T1 and T2 weighted images. Nodular hypointensities seen peripherally within this lesion on both T1WI and T2WI were thought to represent hemosiderin.
Contrast enhancement was not well appreciated. Imaging features are characteristic for craniopharyngioma though the intra ventricular location is unusual. Diagnosis was confirmed on histopathology following near-complete excision of the lesion performed through a frontal craniotomy.

Craniopharyngiomas are relatively common childhood intra cranial tumors which account for about 6-9% of all childhood tumors with a peak incidence in the second decade of life and a second peak in the fifth to sixth decade of life.They are known to arise from squamous epithelial rests which are thought to be remnants of Ratke's pouch, located in the pars tuberalis along the pituitary stalk. Therefore, these tumors grow in the supra sellar or less frequently in the intra sellar region, but are also found in locations like the sphenoid, tuberculum sella, nasopharynx, and the third ventricle.

Further reading :
Jeffrey Rush, John Kusske, Don De Feo, Henry Fribam. Inraventricular craniopharyngioma. Neurology 1975; 25 : 1094-6. M Banna. Review article. Craniopharyngioma - based on 160 cases. BJR 1976; 49:206-223.

Contribution : Dr. Prashant Shetty, Dr Manu Shroff, Dr Harsh Merchant