Vascular solitary fibrous tumor with "floret" cells or giant cell angiofibroma? A lingual example highlighting the overlapping characteristics of these entities and positive immunoreaction for estrogen and progesterone receptors.

Recent literature suggests that giant cell angiofibroma (GCAF) is a variant of solitary fibrous tumor (SFT) and not just a related lesion. Herein we present a case of apparent SFT with giant cells, including floret cells and focal pseudovascular areas, which are defining features of GCAF. The tumor occurred in the tongue of an 84-year-old female and depicted an encapsulated, patternless spindle cell proliferation in a fibromyxoid stroma with focal dense collagenous areas and scattered floret-type multinucleated giant cells seen primarily in the periphery, as well as pseudovascular spaces, numerous capillaries, and hemangiopericytomalike areas. Immunohistochemical investigation revealed positive staining for CD34 and positive immunoreaction for estrogen and progesterone receptors. We support the present notion that GCAF is a histologic subtype of SFT.