Introduction: Hypophysitis, an inflammatory condition of the pituitary, is uncommon and can be difficult to diagnose clinically. Knowledge remains limited regarding its natural history and the best approach to management.
Methods: A multi-center clinical case series was assembled. Hypophysitis was diagnosed histopathologically or clinically in the presence of: hypopituitarism, DI, sella/pituitary stalk-based mass on MRI, autoimmune history, positive pituitary antibodies or ipilimumab use.
Results: Data was collected on 20 patients (6 men, 14 women): 14 had histologically-confirmed hypophysitis, 6 clinically-diagnosed. Average follow-up was 61 months. Hypopituitarism-related symptoms was the most common presentation, confirmed in 19 patients: 11 had 2-3 affected axes, 4 isolated ACTH deficiency and 6 DI. Headache was common (12), with abnormal vision in 5. 9 patients had an autoimmune history. Pituitary antibodies were tested in 2 patients, both positive, one with no known autoimmune disease. A mass lesion, commonly enhancing, was the most frequent radiologic abnormality (14), with an enlarged pituitary in 5. 7 patients had stalk thickening with a dural tail in 3. One patient with ipilimumab use had no significant MRI abnormalities. 14 patients underwent pituitary surgery. Hypophysitis was suspected preoperatively in only 4; the remaining patients had a presumed macroadenoma. Histopathological-diagnoses were lymphocytic (10), granulomatous (3) and xantho-granulomatous (1). Postoperatively, headaches improved in 9/10, pituitary function improved in only 2, radiologic changes improved in 5/10. 3 patients had symptomatic relapses treated with supra-physiological corticosteroids; in 2 with multiple relapses steroid-sparing agents were successfully used. 10 of 11 with long-term control received only replacement corticosteroid doses. The 6 patients with clinically-diagnosed hypophysitis had less severe clinical presentation and more subtle MRI findings. Apart from 1 case with DI alone, all had ACTH deficiency with other affected axes in 3. Symptoms resolved in all patients with only pituitary replacement therapy. 2 patients with progress imaging had no progression.
Conclusions: In clinically-suspected hypophysitis, patients appear to do well with pituitary replacement therapy alone. Patients with mass lesions may benefit from surgical debulking for symptom relief with supra-physiological and steroid-sparing agents reserved for the minority with relapsing disease.