Plasma cell granuloma of the hypothalamic region.

Two patients suffering from diabetes insipidus, with additional symptoms of impaired vision and signs of panhypopituitarism and increased intracranial pressure, showed a normal sella tursica in the X-ray examination of the skull but large, dense space-occupying lesions in the hypothalamus on CT scans of the brain. NMR performed in one patient disclosed suprasellar growth of a hypothalamic lesion. Proliferation of lymphoplasmocytes and mature plasma cells was seen by light microscopic and electromicroscopical examination of biopsy samples in both cases; histiocytes and multinucleated giant cells were absent; tuberculosis, syphilis and sarcoidosis were ruled out by appropriate tests. Plasma cells exhibited polyclonal immunoglobulin expression as revealed by immunocytochemistry using the PAP method. Taken together these features are typical of plasma cell granuloma. Transitory remission after radiotherapy was obtained in one patient.