Granulomatosis with Polyangiitis Presenting as Hypophysitis

A 20-year-old healthy woman presented to a local hospital with 3 months of headaches and fatigue and 3 weeks of intermittent fevers to 40°C. Physical examination was normal. White blood cell count was 6.1 × 109/L, hemoglobin 10 g/dL, sodium 153 mmol/L, and creatinine 0.80 mg/dL. Magnetic resonance imaging demonstrated a 2.1 × 1.8 × 0.9-cm cystic sellar lesion. Hormone testing revealed panhypopituitarism. Lumbar puncture showed white blood cell count 0.220 × 109/L, 98% mononuclear cells, red blood cell count 3 × 109/L, normal glucose and protein, and sterile cultures.