Renal cell carcinoma : Epidemiological profile and histopathological features

Objective: Nowadays, with the use of advanced imaging methods, the incidence of renal cell carcinomas (RCCs) has increased steadily and they have become recognizable at early stage. Morphologically and immunophenotypically, RCCs are divided into many different types and are divided into three main subtypes. Each type has differences in terms of genetics, biology, and behavior. The objectives of this study is to investigate the histopathological features of tumor specimens of patients operated with diagnosis of RCC. Materials and Methods: The pathology specimens and reports of 77 patients with RCC who underwent radical or partial nephrectomy were reviewed retrospectively. Descriptive and clinical data of the patients were obtained. The size, lateralization, focality, histopathological type, Fuhrman nuclear grading system (NGS), sarcomatoid change, renal sinus and vein invasions, perirenal fat tissue invasion, hilar fatty tissue invasion, ureter surgical margin, and primary tumor stage of RCC were determined. Results: According to the histopathologic type, 77.9% of the patients had clear cell RCC, 10.4% chromophobe RCC, 9.1% papillary RCC, and 2.6% multilocular RCC. The Fuhrman NGS values were 5.2% for grade 1, 61% for grade 2, 26% for grade 3, and 7.8% for grade 4. There were sarcomatoid features in only 7.8% of the patients. There were 6 patients (7.8%) with renal sinus invasion, 3 patients (3.9%) with renal vein invasion, 8 patients (10.4%) with perirenal adipose tissue invasion, 2 patients (2.6%) with hilar fat tissue invasion, and 2 patients (2.6%) with tumors at the ureter surgical margin. Pathological changes were significantly differentiated according to gender except for the primary tumor stage. Conclusion: RCCs are divided into many different types and each type has differences in terms of genetics, biology, and behavior. Due to this, the pathologist must differentiate cell types routinely by morphology and immunohistochemical markers as well as by cytogenetic and molecular genetic analysis particularly when the cell type is equivocal