title: Heavily melanotic perivascular epithelioid clear cell tumor of the kidney.
abstract: A black-colored and well-circumscribed renal tumor in a 71-year-old woman is reported. The tumor was unique in that it was rich in vasculature and exclusively composed of perivascular epithelioid clear cells. Morphological features were reminiscent of conventional renal cell carcinoma (RCC). However, immunohistochemical examinations showed that the tumor cells did not express any epithelial markers, but diffusely and intensely expressed a melanocytic marker, gp-100/HMB-45. Another striking feature of the tumor was a large amount of cytoplasmic pigment that made the tumor wholly black. The pigment was not stained with Berlin-blue, completely bleached with potassium permanganate, and stained with Fontana-Masson staining, which suggests that the pigment was melanin. Morphological features and immunohistochemical findings indicated that the present tumor was an extreme example of a perivascular epithelioid clear cell tumor with a large amount of melanin, which has not been previously reported. One should be aware of the pure form of perivascular epithelioid clear cell tumor of the kidney because it is sometimes very difficult to differentiate this tumor from conventional RCC. Immunohistochemical examinations and the presence of cytoplasmic melanin can help the differentiation.
authors.affiliation: Department of Pathology and Laboratory Medicine, The City Hospital of Ikeda, Osaka, Japan. adachi@patho.med.osaka-u.ac.jp
authors.forename: Shiro
authors.initials: S
authors.lastname: Adachi
authors.forename: Masato
authors.initials: M
authors.lastname: Hanada
authors.forename: Yoshiyuki
authors.initials: Y
authors.lastname: Kobayashi
authors.forename: Kohichi
authors.initials: K
authors.lastname: Tsutahara
authors.forename: Shin-ichiro
authors.initials: S
authors.lastname: Fukuhara
authors.forename: Naoki
authors.initials: N
authors.lastname: Mori
authors.forename: Tsuneo
authors.initials: T
authors.lastname: Hara
authors.forename: Hideyo
authors.initials: H
authors.lastname: Mukai
authors.forename: Emi
authors.initials: E
authors.lastname: Shimasaku
authors.forename: Masaru
authors.initials: M
authors.lastname: Kawai
authors.forename: Naoto
authors.initials: N
authors.lastname: Kishikawa
authors.forename: Seiji
authors.initials: S
authors.lastname: Yamaguchi
mesh_terms: D018262:Adenocarcinoma, Clear Cell / Q000378:metabolism / Q000473:pathology*; D000368:Aged; D000951:Antigens, Neoplasm; D002292:Carcinoma, Renal Cell / Q000473:pathology; D003937:Diagnosis, Differential; D015622:Epithelioid Cells / Q000378:metabolism / Q000473:pathology*; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D002479:Inclusion Bodies / Q000378:metabolism; D007680:Kidney Neoplasms / Q000378:metabolism / Q000473:pathology*; D008543:Melanins / Q000378:metabolism*; D058950:Melanoma-Specific Antigens; D008562:Membrane Glycoproteins / Q000378:metabolism; D009363:Neoplasm Proteins / Q000378:metabolism; D058951:gp100 Melanoma Antigen
chemical_list: D000951:Antigens, Neoplasm; D008543:Melanins; D058950:Melanoma-Specific Antigens; D008562:Membrane Glycoproteins; D009363:Neoplasm Proteins; C548637:PMEL protein, human; D058951:gp100 Melanoma Antigen