title: HMB-45 negative clear cell perivascular epithelioid cell tumor of the skin.
abstract: The first case of cutaneous clear cell perivascular epithelioid cell tumor (PEComa) with negative HMB-45 marker is presented. The tumor was a nodule 3x2 cm in size, located on the right foot in a 60-year-old man. The lesion consisted of large irregularly shaped cells with clear cytoplasm, negative for S-100 protein, HMB-45, Melan-A, pancytokeratin, epithelial membrane antigen and CAM5.2. Multifocal positivity for desmin, microphthalmia transcription factor and tyrosinase was found. The diagnosis of cutaneous PEComa of clear cell type was made. Clear cell change is a very unusual finding in PEComa and may pose problems in diagnostic differentiation from other clear cell cutaneous lesions that may be excluded with immunohistochemistry. In our case, the HMB-45 negativity may be explained by extensive clear cell change. Additional studies are necessary to accept the clear cell cutaneous HMB-45 negative PEComa as a new variant of perivascular epithelioid cell tumor.
authors.affiliation: Institute of Anatomic Pathology, Rovereto Hospital, Rovereto, Italy. teresa.pusiol@apss.tn.it
authors.forename: Teresa
authors.initials: T
authors.lastname: Pusiol
authors.forename: Doriana
authors.initials: D
authors.lastname: Morichetti
authors.forename: Maria Grazia
authors.initials: MG
authors.lastname: Zorzi
authors.forename: Surace
authors.initials: S
authors.lastname: Dario
mesh_terms: D014408:Biomarkers, Tumor / Q000032:analysis; D003937:Diagnosis, Differential; D006801:Humans; D008297:Male; D058950:Melanoma-Specific Antigens / Q000032:analysis; D008875:Middle Aged; D054973:Perivascular Epithelioid Cell Neoplasms / Q000473:pathology*; D012878:Skin Neoplasms / Q000473:pathology*; D058951:gp100 Melanoma Antigen
chemical_list: D014408:Biomarkers, Tumor; D058950:Melanoma-Specific Antigens; C548637:PMEL protein, human; D058951:gp100 Melanoma Antigen