[Cystic ectopic pituitary adenoma: report of a case].

A 68-year-old man was admitted with suprasellar cystic tumor with obstructive hydrocephalus, and complaining of slowly progressive memory disturbance, gait disturbance and urinary incontinence. Neurological examination revealed bilateral visual disturbance and disorientation. Skull X-ray films revealed no dilatation of sella turnica and mild erosion of the dorsum sellae. A cystic suprasellar tumor was revealed extending upward to the third ventricular floor and the solid part of the tumor was homogeneously enhanced with Gd-DTPA on MRI. The T1-weighted sagittal MR image revealed a normal pituitary gland and the diaphragma sellae below the tumor. The tumor was totally removed via a bifrontal basal interhemispheric approach, and the tumor was attached to the pituitary stalk and was not contiguous with the pituitary gland. The histological diagnosis was sinusoidal type of chromophobe and non-functioning adenoma. Postoperative MRI revealed a preserved normal pituitary gland and the stalk. To our knowledge, only 11 cases of suprasellar ectopic pituitary adenoma have been reported. We reviewed their neuroradiological features and discussed the pathogenesis. In particular, cystic and nonfunctioning suprasellar ectopic pituitary adenoma may be difficult to distinguish from craniopharyngioma.