Oncocytic papillary renal cell carcinoma with inverted nuclear pattern: Distinct subtype with an indolent clinical course
Department of Pathology, University of Ulsan College of Medicine, Asan Medical Center, Seoul, Korea. Pathology International
(Impact Factor: 1.69).
04/2009; 59(3):137-46. DOI: 10.1111/j.1440-1827.2009.02341.x
Reported herein are seven cases of a histologically distinct oncocytic papillary renal cell carcinoma (OPRCC) with an inverted nuclear pattern. To define its prognostic significance, the clinicopathological features of OPRCC were compared to those of types 1 and 2 PRCC. The median age of the seven patients was 67 years. Grossly, tumors were well-circumscribed and small (1.2 cm +/- 0.4 cm). Microscopically, the OPRCC were composed of well-developed thin papillae, lined with a single layer of cuboidal-to-columnar oncocytic cells. The tumor cells had round-to-oval nuclei and eosinophilic granular cytoplasm, which was strongly positive for anti-mitochondrial immunostaining. The nuclei were characteristically polarized toward the surface of the papillae and contained mostly small nucleoli. The tumors had high expression of alpha-methylacyl-coenzyme A racemase, CD15, CD117, cytokeratin (CK) 7, E-cadherin, epithelial membrane antigen, MOC 31, mucin-1, vascular endothelial growth factor and vimentin, low expression of CD10 and Ki-67, and no expression of CK20. Genetically, gain of chromosomes 3p, 11q, and 17q, and loss of chromosome 4q was observed. All seven patients were alive with no recurrence or metastasis at a mean follow-up time of 37.1 +/- 23.7 months. In conclusion, OPRCC show unique pathological features with indolent clinical behavior and are more similar clinicopathologically to type 1 than to type 2 PRCC.
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ABSTRACT: Histologic analysis of renal tumors usually enables accurate diagnosis, but some tumors may show overlapping histopathologic features, which makes classification difficult. Diagnosis can be extremely challenging in tumors showing oncocytic change, mainly for oncocytomas, chromophobe carcinoma, papillary carcinomas with eosinophilic cells (type 2), and conventional renal cell carcinomas with eosinophilic oncocytic-like cells. The purpose of the present study is to analyze whether the patterns of immunohistochemical expression can help differential diagnosis of these tumors.
A thorough review of the files of the Department of Surgical Pathology, Fundación Jiménez Díaz, Madrid, Spain has retrieved 308 records of renal cell carcinomas in the last 12 years, with 15 renal oncocytomas (RO), 28 papillary carcinomas (PRCC), and 13 chromophobe carcinomas (CHRCC). We have performed immunohistochemistry on representative paraffin blocks from 9 oncocytomas, 11 chromophobe carcinomas, 10 papillary carcinomas, and 11 conventional cell carcinomas with oncocytic cells, from which we had suitable material. The immunohistochemical panel included CD117, α-methylacyl-coenzyme A racemase, CD10, p53, progesterone receptors, and cytokeratins 7 and 20.
Our results show a considerable overlap between immunohistochemical expression in these tumors. Although immunohistochemistry can be helpful in some difficult cases, no markers allow a clear-cut distinction between these tumors, and diagnosis must still rely on morphologic features and histochemical techniques, as well as on molecular techniques when available.
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ABSTRACT: The following report describes the computed tomographic (CT) features of oncocytic papillary renal cell carcinoma (OPRCC), a new subtype. An experienced genitourinary pathologist identified each tumor as type 1 or 2, oncocytic, or other. Two radiologists independently reviewed CT images and assessed maximal tumor diameter, degree of homogeneity, calcification, enhancement, and growth pattern. The 6 OPRCC lesions varied from 1.8 to 5 cm in diameter with a mean of 3.5 cm. Three of the oncocytic lesions were staged T1a, 2 T1b, and 1 T3a. All lesions displayed exophytic growth and were confined to the kidney. Five of the 6 lesions were smooth, and 1 was lobular. Four were homogenously enhancing, whereas 2 were heterogeneously enhancing. The mean (SD) corticomedullary phase enhancement was 70.6 (21.7) HU, nephrographic phase was 69.9 (13.3) HU, and excretory phase was 58.7 (6) HU. In conclusion, OPRCC is a newly described subtype that has CT features similar to type 1 papillary renal cell carcinoma.
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