Review of xanthomatous lesions of the sella.

Xanthomatous lesions of the sellar region have traditionally been divided into two separate categories, xanthomatous hypophysitis (XH) and xanthogranuloma (XG) of the sellar region. The seminal article on XH, a condition typified by foamy histiocytes and lymphoplasmacytic infiltrates in the pituitary gland/sellar region, but usually little or no hemosiderin pigment, detailed three patients. However, most reports since that time have been single cases, making understanding of the entity difficult. In contrast, the seminal report on XG, characterized by sellar region cholesterol clefts, lymphoplasmacytic infiltrates, marked hemosiderin deposits, fibrosis, multinucleated giant cells around cholesterol clefts, eosinophilic granular necrotic debris, and accumulation of macrophages, included 37 patients, allowing more insights into etiology. Few examples could be linked to adamantinomatous craniopharyngioma, and although ciliated epithelium similar to that of Rathke cleft cyst (RCC) was identified up to 35% of the 37 cases, it could not be proven that XG was related to hemorrhage into RCC. Case reports since that time, however, occasionally linked XG to RCC when an etiology could be identified at all, and a few recognized that a spectrum exists in xanthomatous lesions of the sella. They review literature, adding 23 cases from our own experience, to confirm that overlap occurs between XH and XG, and that the majority-but not all-can be linked to RCC leakage/rupture/hemorrhage. It was suggested that progressive accumulation of hemosiderin pigment in the lesion, possibly caused by the multiple episodes of bleeding, could account for the transition of at least some cases of XH to XG.