Purpose: To describe observations of adenohypophysitis on magnetic resonance (MR) images.
Materials and methods: Clinical, enhanced MR imaging, surgical, and histologic findings were retrospectively studied in four female patients and one male patient with adenohypophysitis who presented with headaches, pituitary insufficiency, or hyperprolactinemia. Results were compared with MR imaging, surgical, and pathologic findings in 128 consecutive cases of newly diagnosed pituitary adenomas.
Results: In two of the four female patients, disease onset was not associated with a recent history of pregnancy. Imaging findings included a slightly lobulated, intensely enhancing pituitary mass (n = 5); enhancement along the infundibulum (n = 4); and adjacent dural enhancement (n = 4). Four patients had extrapituitary involvement. Some of these findings were noted in patients with pituitary adenomas complicated by infarction, hemorrhage, or necrosis.
Conclusion: The observed clinical and MR imaging findings are suggestive of adenohypophysitis; the latter, however, are not specific and may be seen in some complicated cases of pituitary adenoma and other rare forms of pituitary inflammation. Biopsy may be needed to establish the correct diagnosis if a trial of steroid therapy fails.