Extraorbital giant cell angiofibromas.

We herein describe two unusual neoplasms showing histopathologic features consistent with those of giant cell angiofibroma, which was originally described as a neoplasm arising in the orbit in adults: one of them arose in the right submandibular region of a 48-year-old woman and the other in the right parascapular region of a 49-year-old woman. Macroscopically, although the latter was characterized by a lymphangioma-like cystic appearance, both tumors were well circumscribed and encapsulated. Microscopically, in both cases, pseudovascular spaces lined by a discontinuous row of multinucleated cells were seen against a background of spindle-shaped fibroblastic cell proliferation. In the second case, the tumor presented increased cellularity and plump and somewhat atypical nuclei of proliferating fibroblastic cells, compared with the tumor in the first case. Immunohistochemically, the mononuclear and multinucleated cells within these tumors were positive for vimentin and CD 34 but negative for any other antigens, including Factor VIII-related antigen, desmin, alpha smooth muscle actin, myoglobin, S-100 protein, LeuM1, lysozyme, alpha-1-antitrypsin, and cytokeratins (AE1/AE3 and CAM5.2). The features in these cases indicate that giant cell angiofibroma can arise in an extraorbital site in middle-aged patients and presents some histopathologic diversity.