Pituitary Granulomatosis with Polyangiitis Presenting with Central Diabetes Insipidus

We report on a case of limited form of granulomatosis with polyangiitis (GPA) with pituitary involvement which presented with central diabetes insipidus. This rare form of GPA has not been reported in Korea. The patient presented with fever, headache, productive cough, nasal symptoms, and polyuria. Laboratory data and imaging studies demonstrated inflammatory lesions in nasal sinus and lungs. Pituitary stalk thickening and enhancement were observed on brain magnetic resonance imaging. The histopathology of the lung lesions showed chronic active granulomatous inflammation. Polyuria, hyperosmolar hypernatremia, and decreased urine osmolality which responded to synthetic vasopressin analog were consistent with central diabetes insipidus. Based on the clinical findings and histopathological results, a diagnosis of GPA with pituitary involvement was established. Treatment with desmopressin as well as concurrent glucocorticoids and immunosuppressant resulted in clinical improvement. (J Rheum Dis 2015;22:195-199)