ABSTRACT
BACKGROUND: Pleomorphic fibromas are rare flesh-colored benign neoplasms first described in 1989. Their histopathology is notable for nuclear pleomorphism of spindle cells and multinucleate giant cells but lacking mitoses. The cellular origin of these tumors is unknown. This case series describes an additional 18 lesions with discussion of histopathology and immunohistochemistry. METHODS: This case series of 18 pleomorphic fibromas uses immunohistochemical staining for CD34, CD68, factor XIIIa, and S-100 and general histopathologic examination under light microscopy to describe the lesions. RESULTS: Immunohistochemical stains for CD34 showed nearly universal positivity of the pleomorphic spindle cells, although some more focally. The pleomorphic cells were negative for CD68, variably positive for factor XIIIa, and universally negative for S-100. All the lesions showed characteristic nuclear pleomorphism with absent mitoses. Collagen thickening was variable, mucin was absent, and perivascular inflammation was present in all lesions. CONCLUSIONS: Pleomorphic fibromas are fibrous lesions with benign clinical course and histopathologic findings including nuclear pleomorphism. Immunohistochemical staining characteristics of the lesion, along with unique spindle cells and multinucleate giant cells help to differentiate this from other tumors.
Subject(s)
Fibroma/metabolism , Fibroma/pathology , Skin Neoplasms/metabolism , Skin Neoplasms/pathology , Adult , Antigens, CD/metabolism , Antigens, CD34/metabolism , Antigens, Differentiation, Myelomonocytic/metabolism , Collagen , Factor XIIIa/metabolism , Female , Giant Cells/pathology , Humans , Immunohistochemistry , Male , Middle Aged , Mitosis , S100 Proteins/metabolism , Young AdultABSTRACT
Halo formation in association with congenital nevi is uncommon and is postulated to have an immunologic etiology. In this report, we present nine cases of patients with congenital nevi and vitiligo who uniquely developed both halo formation around the nevi in addition to vitiligo formation in distinctly separate locations. While the precise etiology of halo formation and vitiligo remains uncertain, several theories suggest that both phenomena result from an immunologic response to pigment cells, whether in the "normal" skin of vitiligo or in the excessively pigmented congenital nevus.
