Vladimír Bartoš1, Oľga Zacharová1, Dušan Pokorný1, Roman Mráz2, Juraj Mikuláš2, Peter Laurinc2
Aim: The purpose of our study was to evaluate an incidence of ChRCC in a group of patients and to assess the basic clinico-pathological parameters of disease. Material and methods: We evaluated all consecutive cases of histologically verified renal cell carcinomas, that had been diagnosed at the Department of Pathology in Zilina hospital during January 2010 – April 2012. Results: Of the total set of 137 renal cell cancers, we confirmed 5 cases (3.6 %) ChRCCs obtained from 5 subjects (1 man, 4 women) in the age range from 51 to 72 years (average 64.2 years). All tumors grew in the right kidney, they were unifocal, sharply demarcated, and their greatest diameter varied between 2.5 - 6.5 cm (mean 4.3 cm). Four cases corresponded to the pathological stage limited to the kidney (pT1a and pT1b) and one cancer was diagnosed in stage pT3b. Histologically, four lesions represented classic variant and one tumor eosinophilic variant ChRCC. In all cases assessed, Hale‘s colloidal iron stain revealed intesive and diffuse intracytoplasmatic positivity (blue staining) of tumor cells. All cancers showed differentiation grade 1. We found only one lesion with minimal necrotic changes. No case with sarcomatoid changes was present. Conclusion: ChRCC is a rare type of renal cell carcinoma with specific histomorphological features. It can sometimes cause a considerable dilemma in biopsy differential diagnosis, particularly in differentiation from renal oncocytoma, which represents a benign tumor with a completely different prognosis and management. There is also important to search for sarcomatoid changes, that occur most frequently in this type of RCC and that worsen the overall course of the disease.