The reliability of leptin immunostain use for differentiating renal oncocytoma and chromophobe renal cell carcinoma

Abstract

Background The discrimination between chromophobe renal cell carcinoma (ChRCC) and renal oncocytoma (RO) has been a topic of concern in medicine. Because ChRCC is a malignant tumor, whereas RO is a tumor with benign behavior, it is important to distinguish these two entities. We aimed to study the possible differentiation concepts between ChRCC and RO. Aim We attempted to study the pathological features of RO and ChRCC and correlate them focusing on the reliability of leptin immunostain use as a tool in differentiation. Materials and methods A total of 25 cases of renal tumors (17 RO cases and eight ChRCC ones) were studied for clinicopathological features’ correlation and leptin immunohistochemical expression. Results The included cases’ mean±SD age was 53.1±12.7 years, with range of 28–72 years. The male sex slightly exceeded the female one in prevalence of studied renal neoplasms (52 vs. 48%, respectively). Regarding the size of oncocytoma tumors in gross examination, it had a mean±SD of 5±2 cm, whereas that of ChRCC was 7±4 cm. The central scar is present in only four (23.5%) cases of oncocytoma, being absent in most cases (13 cases, 76.5%). In ChRCC, the nuclear grade 2 is the most common in the studied group (62.5%). Regarding leptin immunostaining scores, positive score was found in 13/17 oncocytoma cases, and only 2/8 cases of ChRCC showed nuclear leptin stain, with significant P value of 0.028. Oncocytoma leptin-positive cases represented 86.70%, whereas those of ChRCC represented 13.30% of total cases. Leptin sensitivity was estimated to be 76.5%, specificity 75.0%, positive predictive value 86.7%, negative predictive value 60.0%, with overall accuracy of 76%. Conclusion Leptin immunostain can be of an extreme help in differentiating ChRCC and RO.