Figure 3 Histopathological findings of the resected primary renal tumor following neoadjuvant lenvatinib-pembrolizumab therapy and deferred cytoreductive nephrectomy. (A) Extensive treatment-related changes are present within the primary tumor bed, including fibrosis, hemorrhage, necrosis, and aggregates of foamy macrophages (hematoxylin and eosin [H&E], × 400). (B) Residual viable clear cell renal cell carcinoma composed of tumor cells with abundant clear cytoplasm arranged in nests and cords within a delicate vascular network (H&E, × 400). (C) Sarcomatoid differentiation characterized by spindle-cell proliferation with marked nuclear pleomorphism and loss of conventional clear cell morphology (H&E, × 400). (D) High-power view of the sarcomatoid component demonstrating severe nuclear atypia, hyperchromasia, and pleomorphic tumor cells (H&E, × 1000).