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Int J Clin Exp Pathol 2013;6(7):1392-1399

Original Article
Oncocytic papillary renal cell carcinoma: a clinicopathological study emphasizing
distinct morphology, extended immunohistochemical profile and cytogenetic features

Qiu-Yuan Xia, Qiu Rao, Qin Shen, Shan-Shan Shi, Li Li, Biao Liu, Jin Zhang, Yan-Fen Wang, Qun-Li Shi, Jian-Dong Wang, Heng-Hui Ma,
Zhen-Feng Lu, Bo Yu, Ru-Song Zhang, Xiao-Jun Zhou

Department of Pathology, Jinling Hospital, Nanjing University School of Medicine, Nanjing, China. These two authors contributed equally to this
work.

Received May 13, 2013; Accepted May 27, 2013; Epub June 15, 2013; Published July 1, 2013

Abstract: Papillary renal cell carcinoma (PRCC) is traditionally classified into type 1 and type 2. Recently, an oncocytic variant of PRCC has
been described. We report a series of 6 oncocytic renal papillary tumors (OPRCC) which tended to occur in older patients (mean, 56.8 years)
with a male preference (male-to-female ratio is 5:1). All 6 patients are alive with no evidence of disease after initial resection, showing an
indolent clinical behavior. Histologically, tumors exhibited predominant papillary structure with delicate fibrovascular cores. Papillae were lined
by single layers of cells with large, deeply eosinophilic and finely granular cytoplasms and round regular nucleus. The phagocytosis of tumor
cells was frequently and evidently seen in our cases that hemosiderin-laden tumor cells and foamy tumor cells were noticed in five and four
cases respectively. All tumors were immunoreactive for racemase, vimentin, CD10, and MET and negative for CD117. While E-cadherin, EMA,
and cytokeratin 7 exhibited variable immunopositivity. FISH analysis was performed in five of six cases and found heterogeneous results.
Trisomy of chromosomes 7 was found in three cases and trisomy of chromosomes 17 in two cases. Loss of chromosome Y was noted in one
of four tumors in male patients. MET gene status was also investigated by direct sequencing in all 6 cases and found no distinct mutation in
any case. These results suggest that OPRCC shows distinct morphology, indolent clinical behavior, and similar immunohistochemical and
cytogenetic features with PRCC, seems to be a variant in the PRCC group. Whether the strong expression of MET indicates a potential
therapeutic target is still unknown and requires further investigation in clinical trials. (IJCEP1305018).

Keywords: Kidney, papillary renal cell carcinoma, oncocytic tumors, MET

Address correspondence to: Dr. Xiao-Jun Zhou, Department of Pathology, Nanjing Jinling Hospital, Nanjing University School of Medicine,
Nanjing, Jiangsu 210002, China. Tel: 86-25-80860191; Fax: 86-25-80860191; E-mail: zh_xjzhou81@yahoo.com.cn