Histopathological array of lesions in nephrectomies with emphasis on immunohistochemical expression of carbonic anhydrase IX in renal cell carcinoma – A 5-year experience in South India

Objectives: The present study aimed to assess various pathological entities encountered in nephrectomy specimens received in our tertiary care teaching hospital in South India to assess the immunohistochemical expression of carbonic anhydrase IX (CA IX) in various subtypes of renal cell carcinomas (RCCs), and to evaluate its usefulness as a diagnostic and prognostic marker in RCCs. Materials and Methods: The present study was a 5-year retrospective study performed in a teaching hospital. All nephrectomy specimens were routinely fixed, grossed, processed, and sectioned for histopathological evaluation. Immunohistochemistry for CA IX expression was performed manually in all cases diagnosed as RCCs. Statistical analysis: All data were tabulated in Microsoft Excel 2020, and means and standard deviations were calculated using the same. Results: A total of 102 patients were included in the study, with the most common age group being the fifth decade of life and female preponderance. CA IX expression was observed in 100% of clear cell carcinomas, and staining intensity varied with the nuclear grade of the tumor. Conclusions: Non-neoplastic lesions were the most common cause of nephrectomy in our study region. Clear cell RCC is associated with the highest expression of CA IX and seems to be associated with lower nuclear grade and lower T stage; hence, it may serve as a prognostic marker for such cases.