Recovery from lymphocytic hypophysitis associated with painless thyroiditis: clinical implications of circulating antipituitary antibodies.

Lymphocytic hypophysitis usually occurs in the antepartum or postpartum period and recovery of pituitary dysfunction has not been documented in most cases reported previously. We present a 50-year-old woman with lymphocytic hypophysitis who spontaneously recovered from panhypopituitarism over 18 months with the disappearance of an intrasellar mass. Although lymphocytic hypophysitis is thought to be an autoimmune disease, the clinical and pathogenetic significance of circulating antipituitary autoantibodies has not been clarified. Antipituitary antibodies were studied by immunofluorescence in blood samples obtained during the whole clinical course in this particular patient. Antibodies against rat pituitary cytosol were positive during the period of hypopituitarism and became negative when pituitary function recovered. Antibodies reacting with intact prolactin-secreting rat GH3 and corticotropin-secreting mouse AtT-20 cells were also positive during her period of hypopituitarism. They remained positive for several years after the recovery of pituitary function. We conclude that circulating antibodies against rat pituitary cytosol are good markers of pituitary inflammation in this patient. The other point to be emphasized in this case is the simultaneous development of painless thyroiditis and lymphocytic hypophysitis. We have discussed the pathogenic relationship of these two diseases on the basis of similar cases reported previously.