Lymphocytic adenohypophysitis mimicking a pituitary macroadenoma

A 24-year-old woman developed headache and rapidly progressive visual distu rbances during the last trimester of her first pregnancy. Magnetic resonanc e tomography (MRI) of the brain documented an intra- and suprasellar mass l esion. For preservation of vision, transsphenoidal microsurgical decompress ion was performed. Immediately postoperatively, visual acuity improved and hemianopia resolved. Histological examination yielded the diagnosis of prim ary lymphocytic adenohypophysitis. This is a rare inflammatory pituitary di sease. There are no typical clinical, laboratory, or radiological findings that allow precise preoperative diagnosis. Even though this autoimmune diso rder is principally steroid-responsive, an improvement of visual disturbanc es under steroid therapy cannot be predicted, Therefore, surgery is justifi ed not only to establish the diagnosis, but also to restore vision by decom pression of the optic nerves and the chiasm.