Figure 2 Hematoxylin and eosin (H&E) stain, (x100): Left: tumor composed of spindle cells arranged in interlacing bundles and fascicles Right: tumor cells with oval to elongated nuclei having blunted ends
Immunohistochemistry was done and tumor cells showed diffuse positivity with smooth muscle actin (SMA) and focal positivity for desmin (Figure 3). Cytokeratin was negative. A final diagnosis of renal leiomyosarcoma, high grade (Grade 2) using the French Federation of Cancer Centers System was made. The renal leiomyosarcoma was staged as pT3bN0M0 , meaning the tumor had extended into the renal vein without evidence of lymph node involvement or distant metastasis at the time of diagnosis.