Renal leiomyosarcoma with soft tissue metastasis: An unusual presentation.

Primary renal sarcomas are exceptionally rare, constituting 1% of all malignant renal tumours. Since the prognosis for a renal sarcoma is particularly poor, differentiation from sarcomatoid renal cell carcinoma (RCC) is necessary. Histopathology and immunohistochemistry are the only modes of diagnosing these sarcomas as they have no specific features clinically and radiologically. We report a case of renal leiomyosarcoma which was clinically diagnosed as RCC. Histopathology revealed a spindle cell sarcoma and immunohistochemistry (IHC) confirmed a renal leiomyosarcoma. She also had a liver nodule and mass in the right side of neck and left arm. Biopsy from these sites revealed a similar morphology and IHC confirmed leiomyosarcoma. We report a case illustrating the rarity of this disease and its aggressive nature owing to fatal metastatic potential.