Primary Hypophysitis: Idiopathic Inflammatory Disorders of the Pituitary Gland

Abstract

Summary: Primary hypophysitis is a rare but significant cause of sellar spaceoccupying lesions. Three forms have been described: granulomatous, lymphocytic, and xanthomatous hypophysitis. Current methods cannot diagnose or distinguish these entities before surgery with sufficient certainty. The disease most commonly presents with sellar space-occupying symptoms as a result of pituitary enlargement and hormonal abnormalities such as potentially lethal pituitary insufficiency or hyperprolactinemia. Pituitary insufficiency almost always ensues, with progressive inflammatory destruction of the pituitary tissue. All three disorders clinically and radiologically mimic pituitary adenomas, and the diagnosis is usually made after surgery. Idiopathic giant cell granulomatous hypophysitis is a cryptogenic inflammatory lesion. The diagnosis rests on eliminating secondary causes. Lymphocytic hypophysitis is a chronic autoimmune disorder of the anterior and, rarely, posterior pituitary. Although it is most commonly seen in peripartum women, it may be encountered in either sex and may be associated with other autoimmune diseases. Surgical removal, biopsy, and medical therapy are the three options of therapy. Response to medical therapy is unpredictable, but remissions are reported with steroids. A consensus regarding drug choice timing, duration, and dosage of therapy is lacking, but in preoperatively suspected cases, a therapeutic trial is justified. Surgery results in cure at the expense of potentially viable pituitary tissue. The natural course of these rare disorders is currently unknown, the prognosis is unpredictable, and the choice of effective therapy is yet to be established.