Lymphocytic hypophysitis: report of an unusual case of a rare disorder

A 36-year-old non-pregnant woman presented with a four-month history of progressive visual deterioration and amenorrhea. The latest gestation was 6 years earlier. Hormonal study revealed central diabetes insipidus, hypopituitarism, and slightly increased prolactin level. Ophthalmologic examination showed bilateral hemianopsia. In the magnetic resonance imaging an intrasellar mass with supra and retrosellar extension was found. The mass showed a polylobular aspect with heterogeneous signal within the tissue. The normal neurohypophysis could not be identified. Pterional craniotomy was performed. The pathological examinations revealed fibrous tissue with heavy inflammatory infiltrate composed of lymphocytes and plasma cells, islands of eosinophilic epithelial cells stained positively for chromogranin, GH, ACTH, and PRL and negatively for antibodies directed against HLA-II antigens. This case of lymphocytic hypophysitis was not related to pregnancy and involved the neurohypophysis. We discuss the features that can help to make a preoperative differential diagnosis.