Clinical and histopathological features of carcinosarcoma of the renal pelvis: a systematic review of a rare tumor.

Introduction: Carcinosarcoma of the kidney pelvis (CRP) is a rare but not exceptionally unique tumor in which in literature are reported almost only case studies and small series. We aim to provide a comprehensive overview of the disease, examining epidemiology, symptoms, pathological features, treatment and outcomes which are still missing, in order to offer a landmark paper to urologists which have to manage patients with this type of disease.

Evidence Acquisition: A review of the current literature was conducted through the NCBI PubMed database in June 2017 following the updated PRISMA guidelines. The filters used for the research were: "carcinosarcoma renal pelvis," "carcinosarcoma kidney pelvis," and "urinary tract carcinosarcoma." Only studies with confirmed histological diagnosis of CRP and a description of patient characteristics (demographics and/or pathological) were included in the review.

Evidence Synthesis: Only 15 studies fulfilled the inclusion criteria. The main symptom at presentation was macroscopic hematuria, followed by abdominal pain. The carcinomatous pattern made of transitional cell carcinoma in 73.3% of patients and squamous carcinoma in 33%, while the sarcomatoid was spindle cells in 40% of patients, chondrosarcoma and undifferentiated in 33.3%. Despite radical surgical treatment was performed in all patients, there are no articles reporting a survival rate of more than two years.

Conclusions: Carcinosarcoma of the kidney is a rare tumor of which little is known, especially about pathogenesis and oncological outcomes in the different therapeutic approaches described. Current literature is almost exclusively a case report that does not provide adequate information especially about survival and progression free survival. The creation of a shared database could in a matter of years lead us to increase the information about the oncological outcomes of the various possible treatments.