Lymphocytic adenohypophysitis: skull radiographs and MRI

Abstract

We report the skull radiograph, CT and MRI findings in three patients with lymphocytic adenohypophysitis mimicking pituitary adenoma. All cases were associated with pregnancy. CT demonstrated a pituitary mass but did not differentiate lymphocytic adenohypophysitis from pituitary adenoma. The skull radiographs showed either a normal sella turcica or minimal abnormalities; they did not show ballooning or destruction. The MRI appearances were distinctive: relatively low signal on T1-weighted images; preservation of the bright posterior pituitary lobe despite the presence of a relatively large pituitary mass, less common in macroadenomas; marked contrast enhancement compared with pituitary macroadenomas; and dural enhancement adjacent to a pituitary mass.