Chromophobe renal cell carcinoma, oncocytic variant: A proposal of a new variant giving a critical diagnostic pitfall in diagnosing renal oncocytic tumors

Naoto Kuroda, Azusa Tanaka, Tadanori Yamaguchi, Kotaro Kasahara, Keishi Naruse, Yosuke Yamada, Kanako Hatanaka, Nobuo Shinohara, Yoji Nagashima, Shuji Mikami, Mototsugu Oya, Takeru Hamashima, Michal Michal, Ondrej Hes

Research output: Contribution to journalArticlepeer-review

33 Citations (Scopus)


In chromophobe renal cell carcinoma (RCC), two forms of typical and eosinophilic variants have been reported to date. We have previously reported a new variant of chromophobe RCC, namely an oncocytic variant. However, little is known on the histological features of this variant. In this article, we report such five cases. Macroscopically, the tumor was well demarcated, but unencapsulated. The cut surface of the tumor showed brown in color, but neither hemorrhage nor necrosis was seen. Microscopically, the tumor consisted of predominant tubular configuration with or without various proportion of solid-sheet pattern. In one tumor, tumor cells microscopically invaded branches of renal vein. In addition, the constituting cells were characterized by the oncocytic cytoplasm, trivial to minimal variation in tumor size, indistinct to slightly distinct cell border, centrally located round nuclei and the absence of perinuclear halo. These characteristics entirely resembled renal oncocytoma. However, neoplastic cells immunohistochemically showed the diffuse and strong labeling for cytokeratin 7 and mitochondrial antigen in all cases. In addition, in fluorescence in situ hybridization (FISH) study the loss of more than four chromosomes among chromosomes 7, 10, 13, 17 and 21 was confirmed in all tumors and the diagnosis of chromophobe RCC was rendered. In conclusion, we propose a new variant, namely an oncocytic variant, of chromophobe RCC morphologically resembling renal oncocytoma and biologically showing characteristics of chromophobe RCC, and this recognition is practically crucial in the differential diagnosis from renal oncocytoma.

Original languageEnglish
Pages (from-to)49-55
Number of pages7
JournalMedical Molecular Morphology
Issue number1
Publication statusPublished - 2013 Mar
Externally publishedYes


  • Chromophobe RCC
  • Cytokeratin 7
  • FISH
  • Mitochondria
  • Multiple losses of chromosomes
  • Oncocytic variant
  • Tubular pattern

ASJC Scopus subject areas

  • Pathology and Forensic Medicine
  • Molecular Biology


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