Hypothalamic demyelination causing panhypopituitarism

Hypothalamic involvement in multiple sclerosis (MS) and neuromyelitis optica spectrum disorder (NMOSD) is rare and endocrinopathies involving the hypothalamic–pituitary axis in patients with demyelinating conditions have rarely been reported. We present two cases of MS/NMOSD with associated hypothalamic–pituitary involvement and subsequent hypopituitarism, including the first report of a patient with hypothalamic demyelination causing panhypopituitarism. Differential diagnoses, including alemtuzumab‐related and primary pituitary pathology are discussed.