title: Sclerosing hemangioma of the lung in a young woman with cutaneous melanoma: the role of electron microscopy in preventing an erroneous diagnosis of metastasis.
abstract: A young woman with a melanoma of the left forearm was found to have a right lung mass. This was initially interpreted as metastatic melanoma on the basis of clinical, radiographic, and light microscopic features, together with positive staining of tumor cells with antibody HMB-45. Electron microscopic examination performed for confirmation of the diagnosis revealed no evidence of melanocytic differentiation. Instead, there were features suggestive of the alternative diagnosis of sclerosing hemangioma (SH). This diagnosis was confirmed with additional immunocytochemical stains. To the authors' knowledge this is the first report of HMB-45 positivity in SH. This case illustrates a potentially disastrous diagnostic pitfall in interpreting lung tumors in patients with melanoma, and the vital role of electron microscopy in resolving conflicting and/or misleading immunocytochemical results.
authors.affiliation: Department of Pathology, Oregon Health Sciences University, Portland, Oregon 97201, USA. weeksd@ohsu.edu
authors.forename: Douglas A
authors.initials: DA
authors.lastname: Weeks
authors.forename: Samuel P
authors.initials: SP
authors.lastname: Hammar
authors.forename: Anne E
authors.initials: AE
authors.lastname: Rader
authors.forename: Richelle L
authors.initials: RL
authors.lastname: Malott
authors.forename: Gary W
authors.initials: GW
authors.lastname: Mierau
mesh_terms: D000293:Adolescent; D000951:Antigens, Neoplasm; D003937:Diagnosis, Differential; D005260:Female; D018219:Histiocytoma, Benign Fibrous / Q000378:metabolism / Q000473:pathology* / Q000648:ultrastructure; D006801:Humans; D007150:Immunohistochemistry; D008175:Lung Neoplasms / Q000378:metabolism / Q000473:pathology* / Q000648:ultrastructure; D008545:Melanoma / Q000378:metabolism / Q000473:pathology* / Q000648:ultrastructure; D058950:Melanoma-Specific Antigens; D008854:Microscopy, Electron; D009363:Neoplasm Proteins / Q000378:metabolism; D009378:Neoplasms, Multiple Primary / Q000378:metabolism / Q000473:pathology* / Q000648:ultrastructure; D012878:Skin Neoplasms / Q000378:metabolism / Q000473:pathology* / Q000648:ultrastructure
chemical_list: D000951:Antigens, Neoplasm; D058950:Melanoma-Specific Antigens; D009363:Neoplasm Proteins