title: Renal epithelioid angiomyolipoma with epithelial cysts: demonstration of Melan A and HMB45 positivity in the cystic epithelial lining.
abstract: Renal angiomyolipoma (AML) may present as rare variants such as epithelioid and AML with epithelial cysts posing difficulties for the diagnosis to the surgical pathologist. We report a case of a 46-year-old male patient presenting a 5-cm solid tumor in the lower pole of the left kidney, with cystic changes at cut surface. The tumor exhibited 95% of epithelioid cells with atypical nuclei. A small focus of typical AML was observed. The immunoprofile of tumor cells was classical of AML including expression of melanocytic markers such as HMB45 and Melan A. We report the immunohistochemical study of the cystic component in an epithelioid AML. In contrast to the immunoreactivity reported in typical AML, the present case shows obvious expression of melanocytic markers in the cystic epithelial lining. This is strong evidence that these cysts are neoplastic and derived from AML, rather than entrapped native collecting duct epithelium.
authors.affiliation: Hospital Aeroporto, Lauro de Freitas, Brazil.
authors.forename: José do Egypto Pereira
authors.initials: Jdo E
authors.lastname: Filho
authors.forename: Daniele
authors.initials: D
authors.lastname: Meneses de Amorim
authors.forename: Gloria Maria Maranhão
authors.initials: GM
authors.lastname: Sweet
authors.forename: Luiz Antonio
authors.initials: LA
authors.lastname: Rodrigues de Freitas
authors.forename: Paulo Roberto Fontes
authors.initials: PR
authors.lastname: Athanazio
authors.forename: Daniel Abensur
authors.initials: DA
authors.lastname: Athanazio
mesh_terms: D018207:Angiomyolipoma / Q000378:metabolism / Q000473:pathology* / Q000601:surgery; D014408:Biomarkers, Tumor / Q000378:metabolism; D003560:Cysts / Q000378:metabolism / Q000473:pathology* / Q000601:surgery; D004847:Epithelial Cells / Q000378:metabolism / Q000473:pathology; D015622:Epithelioid Cells / Q000378:metabolism / Q000473:pathology*; D006801:Humans; D007680:Kidney Neoplasms / Q000378:metabolism / Q000473:pathology* / Q000601:surgery; D058965:MART-1 Antigen / Q000378:metabolism*; D008297:Male; D058950:Melanoma-Specific Antigens / Q000378:metabolism*; D008875:Middle Aged; D016896:Treatment Outcome; D058951:gp100 Melanoma Antigen
chemical_list: D014408:Biomarkers, Tumor; D058965:MART-1 Antigen; C548667:MLANA protein, human; D058950:Melanoma-Specific Antigens; C548637:PMEL protein, human; D058951:gp100 Melanoma Antigen