Pituitary adenoma associated with xanthogranuloma

Abstract

Xanthogranuloma (XG) of the sellar region is a non-neoplastic inflammatory lesion characterized histologically by recent and remote hemorrhage, necrotic debris, fibrosis, chronic inflammation, and cholesterol clefts with associated foreign-body giant cells. The inflammatory lesion was recognized by the World Health Organization in 2000. XG of the sellar region is rare. Cases of pituitary adenoma (PA) with an associated XG (PA/XG) are extremely rare, with a total of 16 cases in the literature. PA/XG lacks specific clinical and radiologic signs, making pre-operative diagnosis challenging. Herein, we report a case of PA/XG, describe the radiologic and pathologic findings, and discuss the role of so-called silent or "subclinical pituitary apoplexy" in the possible histogenesis of PA/XGs.

Keywords: Pituitary adenoma; Sellar xanthogranuloma; Subclinical pituitary apoplexy.

Fig. 1

MRI (A-D) and histopathology (E-I) of pituitary adenoma associated with xanthogranuloma. (A) Sagittal T1-weighted MR image showing lesion with hyperintense foci, reflecting hemorrhage, calcium, lipid or cholesterol (arrow). (B) Axial T2-weighted image showing lesion with mixed signal intensity (arrow). (C) Axial T1-weighted image with contrast showing lesion's cystic component with peripheral rim enhancement (arrow). (D) Coronal T1-weighted image with contrast showing lesion's heterogeneously enhancing solid component (white arrow), cystic component (orange arrow), peripheral rim enhancement (blue arrow) and optic nerve compression (green arrows). There was no evidence of cavernous sinus invasion by Knosp classification . (E and F) Photomicrographs showing pituitary adenoma (PA) and a contiguous xanthogranuloma (XG). (G) Xanthogranuloma comprising focal hemorrhage, necrotic debris and numerous cholesterol clefts. (H) Pituitary adenoma showing a neoplastic proliferation of epithelial cells with a monotonous appearance. (I) Xanthogranuloma showing abundant cholesterol clefts surrounded by foreign-body giant cells (asterisks). [(E-I). paraffin sections stained with hematoxylin and eosin; (E), original magnification 10x; (F and G), original magnification 20x; (H and I), original magnification 40x].