Sarcomatoid renal cell carcinoma with a chromophobe component producing beta-human chorionic gonadotropin

We report a case of sarcomatoid renal cell carcinoma with a chromophobe component showing significant elevation of beta-human chorionic gonadotropin (beta-HCG) in the peripheral blood. A 35-year-old man was hospitalized because of a large tumor of the left kidney and elevated serum levels of beta-HCG. Extended nephrectomy was performed, after which the serum beta-HCG level decreased. However, 3 months later, masses were discovered in the left renal bed and in the lung in association with elevated serum levels of beta-HCG. The patient was rehospitalized and received combination therapy with interferon-alpha and doxorubicin-based multiple chemotherapy (cyclophosphamide, vincristine, doxorubicin, and dacarbazine). The recurrent mass responded extremely well to treatment, and beta-HCG normalized. However, the patient died 14 months after nephrectomy because of eventual resistance to chemotherapy. Sarcomatoid renal cell carcinoma containing beta-HCG positive cells were pathologically diagnosed with immunohistochemical staining in the left kidney. Sarcomatoid renal cell carcinoma is a variant of renal adenocarcinoma which has a poor prognosis. This patient had an extremely rare sarcomatoid renal cell carcinoma associated with serum levels of beta-HCG which were elevated and strongly correlated with morphologic cancer activity. beta-HCG might be a useful serum marker for detecting and monitoring this renal cell carcinoma.