MRI of lymphocytic hypophysitis

Objective To describe the M R findings in patients with lymphocytic hypophysitis (LyH), and to discuss MR diag nostic value and limit in this disease entity and its differentiation with pitui tary adenoma. Methods Five pathologically proven cases of LyH were recruited in this study. The main complaints of the patients were poly dipsia, polyuria, and headache. The preoperative MR images and clinical manifest ations were analyzed retrospectively. Results MR findings of the 5 patients with LyH included enlargement of pituitary gland, stalk thick ening, disappearance of high signal of neurohypophysis on T_1WI, and marked Gad olinium enhancement of the lesions. Homogeneous enhancement was found in 2 cas es, while heterogeneous enhancement was in 3 cases. Involvement of the caverno us sinus and dura mater on dorsum sella and clivus were found in 2 patients. Conclusion The diagnosis of LyH should be suggested when the enlarged pituitary gland is associated with central diabetes insipidus, and wit h/without dysfunction of adenohypophysis.