Teaching NeuroImages: Ma2 encephalitis presenting as acute panhypopituitarism in a young man.

A 21-year-old man presented with headache, hypotonia, hypothermia, and somnolence, deteriorating to a Glasgow Coma Scale score of 3 within days. Hormonal testing revealed panhypopituitarism. His cerebral MRI showed a gadolinium-enhancing lesion in the pituitary gland with adjacent changes to the hypothalamus, midbrain, and basal ganglia (figures 1 and 2). Therapy with prednisolone resulted in rapid improvement. Ma2 antibodies were found in the patient's serum and CSF. FDG-PET demonstrated a tumor mass in the superior mediastinum and histology revealed a mediastinal seminoma. Ma2 antibody-mediated paraneoplastic disease has to be considered as a rare differential diagnosis in patients presenting with acute panhypopituitarism.(1.)