engleski

Renal cell carcinoma- not otherwise specified (RCC- NOS)

Introduction: Unclassified category of renal cell carcinoma (RCC) represents <5% of all renal cell carcinomas. It is rather a diagnostic category than a type of carcinoma, since it indicates morphologically and biologically heterogeneous group of tumors that cannot be included in well- known entities of current classification system (WHO 2016). Case report: We present a case of a 46- year- old male patient with a left kidney tumor discovered during general medical examination. He was referred to a hospital for further analyses and treatment. MSCT scan revealed left kidney reduced in size with exophytic oval tumor, 26 mm in diameter, while scintigraphy demonstrated serious functional damage of the kidney. Elective radical nephrectomy was the treatment of choice. Pathohistological analysis demonstrated tumoral tissue composed of glandular, tubular, papillary and micropapillary formations lined by atypical pseudostratified epithelial cells with eosinophilic cytoplasm and uniform nuclei with focally visible nucleoli. Also, foci of cells with lighter cytoplasm, numerous psammoma bodies, eosinophilic globules and sparse necrosis were present. Tumoral cells were diffusely positive for CK7, PAX 8 and AMACR. Further analysis revealed the presence of a mutation MTOR c.4364_4366del, p. (Glu1455_Trp1456delinsGly). According to pathohistological, immunohistochemical and molecular profile, final diagnosis was unclassified renal cell carcinoma (WHO 2016). Discussion and conclusion: Unclassified category of RCC histologically represents combination of patterns of established RCC subtypes. Also, the presence of mutations such as NF2 loss, ALK translocation, FH deficiency is common. These tumors vary from low- grade exhibiting indolent behavior, but mostly are high- grade tumors having prognostic outcome worse than clear cell RCC. Considering the characteristics of this category, the diagnosis of unclassified RCC represents a diagnosis of exclusion, impossible without careful sampling, histologic assessment and implementation of molecular analysis, which are all important for further treatment decisions, especially the application of targeted therapy.

renal cell ; carcinoma ; NOS

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