Natural course of lymphocytic infundibuloneurohypophysitis.

Natural course of lymphocytic infundibuloneurohypophysitis is poorly understood. A 49-year-old male had noticed being unnaturally thirsty since about two years previously. An enlargement of the pituitary stalk and pituitary gland was thus observed by MR at that time. However, no medical care had been given. Two years later, he was admitted to our hospital due to headache in addition to panhypopituitarism. The histologic features included T cell dominant lymphocytes infiltrating prominently the entire pituitary gland with a small amount of multinucleated giant cells, focal and small necrosis, cholesterin crystals and granuloma. Neither tuberculosis nor Langerhans histiocytosis were observed. In addition, the patient was found to have a unique massive well-encapusulated lesion in the sphenoid sinus, just below the pituitary fossa, consisting of serous fluid, normal columnar epithelium and submucosal fibrosis. This patient had a fairly typical clinical manifestation of lymphocytic infundibuloneurohypophysitis with invason of the posterior lobe and the stalk. The lesion became chronic and leaked to the sphenoid sinus. As a result, chronic hypophysitis with granuloma formation thus occurred. This case may show the course of this disease if not treated.