Abstract
BACKGROUND: Xanthomatous hypophysitis (XH) is an extremely rare form of primary hypophysitis characterized by infiltration of the pituitary gland by mixed types of inflammatory cells, including foamy cells, plasma cells, and small mature lymphocytes. XH manifests as varying degrees of hypopituitarism. Although several previous reports have denied a possible contribution of autoimmune mechanism, the exact pathogenesis of XH remains unclear. CASE DESCRIPTION: We describe the case of a 72-year-old woman with a history of rheumatoid arthritis and Sjögren's syndrome who presented with panhypopituitarism and diabetes insipidus. At the time of her visit, she also experienced relapsed rheumatoid arthritis and Sjögren's syndrome, manifesting as arthralgia. Magnetic resonance imaging (MRI) showed a multicystic mass in the sellar and suprasellar regions. In the course of steroid replacement therapy for hypocortisolism, the patient's arthralgia diminished, and MRI revealed shrinkage of the mass. XH was diagnosed histologically following a transsphenoidal endoscopic biopsy, and it was the oldest case of XH. CONCLUSION: To the best of our knowledge, this patient is the oldest of reported patients diagnosed with XH. Steroid therapy may be effective to XH temporarily. XH should be considered when diagnosing pituitary cystic lesions in elderly patients with autoimmune disease.