Third ventricular lesion masquerading as suprasellar disease

We discuss the case of a patient who presented with a bitemporal visual fie ld disturbance thought to arise from chiasmatic compression secondary to a suprasellar mass. The patient was ultimately diagnosed with medulloblastoma with diffuse intraventricular disease. Careful review of magnetic resonanc e (MR) findings in this case demonstrate the apparent suprasellar mass to b e within the suprachiasmatic recess of the third ventricle. The role of MR imaging in distinguishing between suprasellar disease involving the third v entricle and primary third ventricular lesions is discussed. (C) 1999 by El sevier Science Inc.