Secondary xanthogranulomatous hypophysitis mimicking a pituitary macroadenoma: a case report

Hypophysitis is an extremely rare inflammatory disease that can mimic the clinical and radiological features of a pituitary adenoma. In this case report, we describe a 45-year-old woman with secondary xanthogranulomatous hypophysitis (XGH) who presented with signs of a pituitary macroadenoma. The patient complained of headaches, visual impairment, and amenorrhea-galactorrhea syndrome. Her physical examination was normal. Laboratory investigation revealed corticotropin, thyrotropin, and gonadotropin deficiencies. She also had low visual acuity in her right eye and an altered visual field. Pituitary magnetic resonance imaging revealed an intra and suprasellar mass measuring 13 × 11 × 16 mm, with hemorrhagic necrosis, that was having a discrete mass effect on the patient's optic chiasm and pituitary stalk. The patient was treated with hydrocortisone and levothyroxine, and then transferred to the Neurosurgery department for total transsphenoidal resection of the mass. Histological examination of the tumor permitted a diagnosis of XGH of a remodeled Rathke's pouch cyst to be made. Systemic conditions such as tuberculosis, sarcoidosis, and other granulomatous diseases were excluded. The etiopathogenesis of XGH remains poorly characterized, but it may be a progressive form of lymphocytic hypophysitis or a remodeled Rathke's pouch cyst. Screening for autoimmune pathology and systemic diseases is essential to guide appropriate management.