Inflammatory Hypophysitis – The Spectrum of Disease

Summary

 Background. Inflammatory conditions of the pituitary are rare and consequently there are a number of single case reports of this condition but few reports of series. The condition is often divided into lymphocytic and granulomatous hypophysitis and it has been suggested that these two conditions represent the ends of a spectrum of disease.

 Method. We present our experience with 14 cases of this condition, correlating the presenting symptoms with the neuroradiology, surgical findings and subsequent histology.

 Findings. The subjects (11 female 3 male) ranged in age from 13 to 64 years. Final histopathological diagnoses included 5 cases of lymphocytic hypophysitis, 4 cases of Rathke's pouch cyst with granulomatous response, 2 cases of granulomatous hypophysitis and 1 case with an inflammatory process that did not fit the current classification. Two subjects did not undergo surgery. Headache was a presenting feature in 11 of 14 cases and fever in 3 of 14 cases. Length of symptoms prior to presentation varied from acute onset to 9 years. One case of lymphocytic hypophysitis was associated with pregnancy. Evidence of hypopituitarism was present in 9 of 10 subjects assessed preoperatively. Preoperative radiology showed three patterns of disease: A cystic appearance was common with low signal content on MRI T1 weighting with an enhancing ring and a thickened enhancing stalk (5 patients). 4 patients showed a solid enhancing mass. A third group (2 patients) showed cysts with high signal content on T1 weighting – both of these were Rathke's cysts on histology.

 Interpretation. Overall there were no striking features in the clinical presentation to distinguish pituitary inflammation from pituitary adenoma. The prognosis was generally good.