Xanthomatous pituitary lesions: a report of two cases and review of the literature.

We describe two young men with cystic pituitary enlargement on magnetic resonance imaging (MRI) causing hypopituitarism. The first patient presented acutely unwell with headache and vomiting associated with anterior and posterior pituitary dysfunction. The second patient presented with hypopituitarism after a long history of hypogonadism. In both cases yellow/brown fluid was found at surgery and histological examination revealed inflammatory infiltrate with foamy histiocytes, lymphocytes and multinucleated giant cells containing cholesterol clefts. Full recovery of pituitary function occurred after surgery in the first but not the second patient. The first case is the first documented case of xanthomatous hypophysitis with recovery of pituitary function following surgery. The cases differed in duration of disease, as indicated by the long history of symptoms, the histological finding of marked fibrosis and the lack of recovery of pituitary function in the second. Xanthomatous pituitary lesions categorized in the literature as xanthomatous hypophysitis, xanthogranulomatous hypophysitis and xanthogranuloma of the sellar region have overlapping histological features. Our two cases revealed histological features that do not fit completely into any of the categories but share features of all three. These findings suggest that the various xanthomatous lesions of the sellar region may be a spectrum of a common inflammatory process rather than distinct pathological entities.