title: C-Kit-positive metastatic malignant pigmented clear-cell epithelioid tumor arising from the kidney in a child without tuberous sclerosis.
abstract: We report the first pediatric case of malignant pigmented epithelioid clear-cell tumor arising from kidney; the lesion occurred in a 12-year-old girl without tuberous sclerosis. The tumor was widely metastatic to the retroperitoneum and chest, and the patient died of the disease 9 months after diagnosis, despite active chemotherapy. Pigmented epithelioid clear-cell tumor of the kidney is a rare variant of epithelioid angiomyolipoma and a member of the family of perivascular epithelioid cell tumors (PEComas). The tumor demonstrated overlapping features between clear-cell sugar tumor and epithelioid variant of angiomyolipoma. Tumor cells were positive for HMB-45 expression, negative for any evidence of muscular differentiation, and contained melanin pigment and premelanosomes in the cytoplasm. Diffuse C-Kit (CD117) positivity was identified throughout the tumor. This is the first report of C-Kit-positive malignant PEComas.
authors.affiliation: Department of Pathology and Laboratory Medicine, Alberta Children's Hospital, (Calgary Laboratory Services), Calgary, Alberta, Canada T2T 5C7.
authors.forename: Weiming
authors.initials: W
authors.lastname: Yu
authors.forename: Robert B
authors.initials: RB
authors.lastname: Fraser
authors.forename: David A
authors.initials: DA
authors.lastname: Gaskin
authors.forename: Conrad V
authors.initials: CV
authors.lastname: Fernandez
authors.forename: James R
authors.initials: JR
authors.lastname: Wright
mesh_terms: D018207:Angiomyolipoma / Q000175:diagnosis / Q000378:metabolism* / Q000473:pathology; D002648:Child; D005260:Female; D006801:Humans; D007680:Kidney Neoplasms / Q000175:diagnosis / Q000378:metabolism* / Q000473:pathology; D019009:Proto-Oncogene Proteins c-kit / Q000378:metabolism*; D012186:Retroperitoneal Neoplasms / Q000473:pathology / Q000556:secondary; D013899:Thoracic Neoplasms / Q000473:pathology / Q000556:secondary; D014402:Tuberous Sclerosis
chemical_list: D019009:Proto-Oncogene Proteins c-kit