Managing the unexpected: Carcinosarcoma of the kidney parenchyma A case with the longest follow-up.

Introduction: We present the management of the second reported case of carcinosarcoma of the kidney parenchyma with malignant degeneration of both epithelial and mesenchymal components.

Case Report: A 36-year-old woman came to our attention for an incidental sonographic finding of a lesion in the lower pole of the left kidney. A contrasted computed tomography scan confirmed the presence of a 50 × 52 mm contrasted lesion in the left lower kidney pole. The patient underwent a challenging laparoscopic left partial nephrectomy and para-aortic lymphadenectomy. The histological examination led to the diagnosis of a carcinosarcoma of the kidney parenchyma with malignant degeneration of both epithelial and mesenchymal components. The patient underwent adjuvant chemotherapy with paclitaxel at 175 mg/m plus carboplatin area under the curve 6 intravenously for six cycles. At a follow-up of 42 months, the patient is alive and does not show any local recurrences or distant metastases.

Conclusion: A multi-disciplinary therapeutic approach, combined with an adequate doctor-patient relationship and a close and detailed follow-up, is of fundamental importance in obtaining good outcomes in such rare and challenging cases.