Recurrent Bacterial Meningitis Perpetuated by an Infected Rathke's Cleft Cyst

A 52-year-old woman with a 6-month history of prednisolone treatment for suspected diagnosis of myositis presented 3 months after withdrawal of steroids with headache, nuchal rigidity, fever, nausea, and vomiting. While routine blood work was unremarkable, CSF analysis was consistent with bacterial meningitis. MRI confirmed a non-enhancing pituitary cystic lesion that had been incidentally diagnosed 6 years earlier as a suspected Rathke's cleft cyst (RCC). Under the suspected diagnosis of RCC empyema, the patient underwent transsphenoidal surgery. Neuropathological examination revealed purulent material containing gram-positive cocci within a RCC.