title: Epidermotropic xanthoma mimicking balloon cell melanoma.
abstract: Xanthomas of the skin may mimic balloon cell melanoma because 1) both lesions may exhibit a diffuse dermal proliferation of cytologically similar large vacuolated or clear cells with distinct cytoplasmic membranes, 2) dermal maturation (smaller deep dermal nuclei) is absent in both lesions, 3) melanin pigment is usually absent in balloon cell melanoma, 4) cellular atypia may be minimal in balloon cell melanoma, and 5) mitoses may be absent or rare in balloon cell melanoma. We report a unique xanthoma, which further simulated melanoma by exhibiting epidermotropism and a pseudonesting pattern at the dermal-epidermal junction. The correct diagnosis was made with an immunohistochemical panel revealing tumor cell positivity for CD68 and negativity for S-100 protein and MART-1. Immunohistochemical studies may be required in the critical differential diagnosis of epidermotropic xanthoma and amelanotic balloon cell melanoma.
authors.affiliation: Central Texas Pathology Laboratory, P.A. Waco, Texas 76708, USA.
authors.forename: A D
authors.initials: AD
authors.lastname: Northcutt
mesh_terms: D015703:Antigens, CD / Q000378:metabolism; D015214:Antigens, Differentiation, Myelomonocytic / Q000378:metabolism; D000951:Antigens, Neoplasm; D003937:Diagnosis, Differential; D004817:Epidermis / Q000378:metabolism / Q000473:pathology*; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D058965:MART-1 Antigen; D008545:Melanoma / Q000175:diagnosis* / Q000378:metabolism; D008875:Middle Aged; D009363:Neoplasm Proteins / Q000378:metabolism; D009418:S100 Proteins / Q000378:metabolism; D012878:Skin Neoplasms / Q000175:diagnosis* / Q000378:metabolism; D014973:Xanthomatosis / Q000175:diagnosis* / Q000378:metabolism; D000097382:CD68 Molecule
chemical_list: D015703:Antigens, CD; D015214:Antigens, Differentiation, Myelomonocytic; D000951:Antigens, Neoplasm; D058965:MART-1 Antigen; D009363:Neoplasm Proteins; D009418:S100 Proteins; C067980:CD68 antigen, human; D000097382:CD68 Molecule; C548667:MLANA protein, human