Renal tumor with overlapping distal nephron morphology and karyotype
Department of Pathology, University of Illinois at Chicago, Chicago, Ill, USA.Archives of pathology & laboratory medicine (Impact Factor: 2.84). 12/2004; 128(11):1274-8. DOI: 10.1043/1543-2165(2004)128<1274:RTWODN>2.0.CO;2
Although most renal epithelial tumors are derived from the proximal nephron, approximately 10% are believed to originate in the distal nephron. This latter group encompasses oncocytoma, chromophobe renal cell carcinoma, and several rare types, including collecting duct carcinoma and renal medullary carcinoma. Despite progress in the classification of renal tumors, a small subset of renal carcinomas remains unclassified (ie, renal cell carcinoma, not otherwise specified). We describe a metastatic tumor consisting of cells with overlapping distal nephron morphologies, including foci of oncocytoma, chromophobe renal cell carcinoma, and collecting duct carcinoma, as well as sarcomatoid dedifferentiation. Special stains were inconclusive, and ultrastructural study demonstrated abundant mitochondria and no microvesicles. The karyotype was hypodiploid with 41 chromosomes and abnormalities reported in all 3 phenotypes present. Rearrangements of 1p and of 11q13 previously seen in divergent subsets of oncocytomas were concomitantly present in the current tumor. Thus, this malignancy has features consistent with distal nephron derivation and demonstrates the convergence of the varied tumor morphologies arising within this site. Furthermore, this case exemplifies the value of cytogenetic analysis in the characterization of renal cell carcinoma, not otherwise specified. In view of recent advances in treatment approach, especially for collecting duct carcinoma, further categorization of this nondescript and heterogeneous group of renal cell carcinomas, not otherwise specified, at least by its derivation in relationship to the renal nephron (distal vs proximal), may be of value in the choice of treatment modality.
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ABSTRACT: The classification of renal tumors has evolved from one that initially encompassed only 2 types of tumors, i.e., clear and granular cell carcinomas, to the markedly expanded recent classification that incorporates new entities, some of which are primarily defined by specific molecular abnormalities. Despite these advances, a single tumor category, clear cell carcinoma, still incorporates the majority (approximately 70%) of renal tumors. It is, however, postulated that this single category is likely to encompass several different tumor types that are, at present, undifferentiated. Electron microscopic studies have been pivotal in defining the spectrum of oncocytoma-chromophobe renal cell carcinoma. Cytoplasmic eosinophilia found in some renal cell carcinomas currently classified as clear cell type is under intense study. Tumors that have recently emerged from this group include tumors with translocations involving chromosome Xp11.2, carcinomas associated with neuroblastoma and epithelioid angiomyolipoma. The spectrum of renal tumors seen in younger patients is wider than among older patients, with rare and unusual tumors being more likely seen in younger patients. The author concludes that although the routine application of electron microscopy to kidney tumor diagnosis may not be practical, systematic ultrastructural studies of these tumors may aid in the definition of new entities.
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ABSTRACT: Chromophobe renal cell carcinoma (RCC) and collecting duct carcinoma (CDC) are derived from the collecting duct epithelia, although their morphology, molecular biologic characteristics and clinical behaviors are quite different. Herein is presented a case of RCC possessing the chromophobe RCC and CDC elements occurring in a 64 year-old Japanese woman. The patient was referred to Yokohama City University Hospital with complaints of persistent back pain and fever. Radiologic examinations revealed a left renal tumor, and radical nephrectomy was performed. The patient died with multiple metastases, 8 months after the operation. The resected tumor showed an invasive growth, and its cut surface was heterogenous with hemorrhage and necrosis. Histologically, the tumor was composed of chromophobe elements with dedifferentiation, and CDC elements. The chromophobe and CDC elements had obvious histological transition. Lectin histochemistry and immunohistochemistry confirmed that this tumor was derived from the distal nephron. c-KIT, p53 and Ki67 antigen showed differential localization between the chromophobe and CDC elements, even in the transitional areas. Along with the previous reports, the present case seemed to be composite RCC derived from the collecting duct, which might present clues to elucidate carcinogenesis in the distal nephron.
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ABSTRACT: USEFULNESS OF THE PRESENT RENAL CELL CARCINOMA CLASSIFICATIONS The purpose of classifying neoplasias is to recognize groups with similar progress and prognosis and, if possible, receiving the same treatment. This is why those classifications are systematically being submitted to review and impro- vement through the new technologies. Differentiation of various entities in renal cancer has been comparatively fast, as the new genetic and molecular dis- coveries have confirmed the morphologic criteria of the different cell types, thus making it possible to open new thera- peutic pathways. Using the current WHO classification we recognize subtypes with excellent prognosis (Multilocular cystic renal carci- noma, Type I renal papillary carcinoma, Tubular and fusocellular mucinous carcinoma), other very aggressive ones (Bellini's collecting duct carcinoma, Medullary carcinoma), and also that the sarcomatoid transformation, even in small areas, impacts the prognosis negatively. Childhood-characteristic renal carcinomas associated with chromosome trans- locations have been recognized (genetic fusion TFE3 or TFEB), as well as the family forms of renal carcinoma. Regarding the UICC (International Union Against Cancer) classification, there are a series of aspects under argument (size, venous invasion, microvascular invasion, invasion of the adipous tissue of the renal sinus) that shall be discussed too, since it is possible that some modifications of the TNM might occur in the near future.
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