Endocrine Abstracts

Idiopathic granulomatous hypophysitis is a very rare inflammatory disease of the pituitary gland. Primary hypophysitis represents a difficult diagnostic challenge because it can imitate pituitary adenomas clinically and radiologically. The diagnosis is usually made histologically by hypophysectomy. We herein present a rare case of idiopathic granulomatous hypopysitis diagnosed primarily by pituitary biopsy.

Case: A 50-year-old female patient presented with headache, visual loss and menstrual irregularities over the preceding year. At her first visit at another hospital, TSH level was normal but prolactin level was high (PRL: 115 ng/ml). In her visual field examination, a near total defect on right eye and a peripheral visual field defect on left eye were detected. Pituitary MRI revealed a 17×9×12 mm macroadenoma extending to optic chiasm. Cabergoline therapy was started. When she applied to our clinic 3 months later, pituitary MRI demonstrated a 6 mm microadenoma? and her vision complaints were disappeared; but hypocortisolism and secondary hypothyroidism were detected. Replacement therapies were started and cabergoline was stopped. This unexpected development of pituitary insufficiency necessitated a re-evaluation of MRI screenings. Because our decision was in favor of a possible hypophsitis, trans-sphenoidal pituitary biopsy was performed. Pituitary biopsy demonstrated non-necrotising granulomatous hypophysitis. Possible secondary causes were investigated and no evidence was found. The final diagnosis was idiopathic granulomatous hypophysitis. We decided to follow-up the patient and replacement therapies were continued. The patient had no further complaints.

Conclusion: Idiopathic granulomatous hypophysitis, which is a very rare disease, diagnosed by pituitary biopsy is the main characteristic of our remarkable case. In patients with pituitary insufficiency, considering hypophysitis is a crucial clinical decision especially if they have specific radiological findings because it is highly possible to treat these patients medically and avoid hypophysectomy.