Lymphocytic hypophysitis accompanied by aseptic meningitis mimics subacute meningoencephalitis.

A 66-year-old man was admitted to our hospital with muscle pain, fatigue and appetite loss that had lasted for a month. The patient was somnolent and had nuchal stiffness with a high fever. Cerebrospinal fluid (CSF) tests demonstrated lymphocytic pleocytosis with a decreased CSF-blood glucose ratio. The tests for tuberculous, fungal and carcinomatous meningitis and herpetic meningoencephalitis were negative. Endocrinological exams showed hypopituitarism and diabetes insipidus. A pituitary MRI showed an enlargement of the pituitary stalk. A diagnosis of lymphocytic hypophysitis with aseptic meningitis was made after the exclusion of secondary hypophysitis. Lymphocytic hypophysitis with aseptic meningitis can mimic subacute meningoencephalitis.