Case of the month.  April 1996--pituitary tumor. 
A 20 year old man presented with intermittent diplopia and difficulty focusing his leftward gaze during the past month.  His past medical history was only significant for a dermoid cyst in the posterior fossa which was removed at age 10.  MRI scans demonstrated a perisellar mass, eroding the sphenoid and surrounding the right carotid artery as well as extending into the sella.  A transsphenoidal endoscopic resection was performed.  The tumor was diagnosed as a germinoma (seminoma).  Most germinomas in the brain arise in the pineal, however, germ cell neoplasms (including teratomas, germinomas and non-germinomatous germ cell neoplasms) are not unknown in the perisellar region and typically arise in the hypothalamic region and present with diabetes insipidus, visual disturbances or hypopituitism.