[A clinically diagnosed lymphocytic hypophysitis presenting as recurrent meningitis].

A 55-year-old woman was admitted to our hospital complaining of severe headache with fever and apparent neck stiffness. Neutrophilic pleocytosis was demonstrated in cerebrospinal fluid (CSF) and bacterial meningitis was strongly suspected, but bacterial culture of CSF was negative. After the symptoms normalized within a few days, she developed diabetes insipidus and gadolinium (Gd)-enhancement of the enlarged hypophysis and stalk was observed on cranial MRI. A Lymphocytic Hypophysitis (LH) was clinically diagnosed. Follow-up studies demonstrated spontaneous remission of serological, radiological, and CSF findings, and she was discharged on hormonal replacement therapy with desmopressin. Three months later, she returned to our hospital complaining of headache again under adenohypophysial hypofunction and expanding pituitary lesion on MRI. CSF analysis showed meningitis but there was no evidence of infection by microorganisms. Our diagnosis was relapsing LH with aseptic meningitis, and the patient was administered methylprednisolone pulse therapy, which induced rapid improvement in clinical, endocrinological, and radiological findings. This case showed a possible unique clinical presentation of LH characterized as recurrent aseptic meningitis. It is important to recognize this phenotype of LH, and to prescribe corticosteroid therapy after appropriate endocrinological and radiological studies.