CLINICAL CASE SEMINAR - LYMPHOCYTIC HYPOPHYSITIS - CLINICOPATHOLOGICAL FINDINGS

This report describes the clinicopathological features of 16 patients with lymphocytic hypophysitis and compares the results with the publis hed Literature. There were 2 males and 14 females in this series. In 1 0 of the 14 females (71%), the presentation was associated with pregna ncy. Nine patients (56%) presented with symptoms of an expanding pitui tary sellar mass, 10 (63%) had anterior pituitary hypofunction, 3 had diabetes insipidus (19%). Progressive undiagnosed hypopituitarism led to the demise of 3 patients (19%). Hyperprolactinemia was encountered in 6 patients (38%), and elevated growth hormone levels (GH) resulted in IGF-1 excess in one patient. Computed tomography (CT) and magnetic resonance (MR) imaging revealed features of a pituitary mass mimicking an adenoma in 10 cases (83%). Four patients (25%) had associated auto immune thyroiditis. Morphologic examination of the pituitary and immun ohistochemistry showed a polyclonal lymphoplasmacytic infiltrate as we ll as occasional neutrophils, eosinophils, and macrophages; the chroni c inflammatory process resulted in focal or diffuse adenohypophysial d estruction of variable severity with associated fibrosis. The inflamma tory infiltrate involved the neurohypophysis in 2 cases and one of the se patients had diabetes insipidus; the posterior lobe of two other pa tients with diabetes insipidus was not examined morphologically. We co nclude that lymphocytic hypophysitis should be considered in the diffe rential diagnosis of females with pituitary enlargement presenting in the peripartum period as well as those patients in whom pituitary horm one deficiency and/or excess is noted in association with a co-existin g autoimmune disorder. This clinical suspicion should probably also be extended to include patients presenting with rapidly growing pituitar y masses associated with compressive symptoms with or without pituitar y hormone dysfunction. Because of the transient endocrine and compress ive features of this condition in many instances, conservative treatme nt on the basis of clinical suspicion alone may obviate the need for a ggressive pituitary surgery.