Carcinosarcoma of renal pelvis with immunohistochemical correlation.

Carcinosarcoma, a malignant tumor with biphasic morphology is uncommon in the renal pelvis. Immunohistochemistry (IHC) plays an important role in establishing the diagnosis and differentiating it from other biphasic malignant tumors. We present a rare case of immunohistologically confirmed carcinosarcoma of renal pelvis in a 42-year old female, which possibly developed on a background of multicentric squamous cell carcinoma arising as a consequence of chronic irritation caused by calculi.