A case of metastatic sarcomatoid renal cell carcinoma diagnosed by trismus as the initial symptom

Sarcomatoid renal cell carcinoma (SRCC) is a rare kidney tumor with rapid growth and a poor prognosis. Here we report a case of metastatic SRCC of the right masseter region with trismus as an initial symptom from SRCC of kidney. Computed tomography imaging presented masses in the right masseter region and right kidney. Positron emission tomography also showed widespread 18F-fluorodeoxyglucose uptake masses in their regions with other organs and lymph nodes. Fine-needle aspiration (FNA) cytology for the right masseter mass showed suspicious findings of glandular cell tumor. We then took a biopsy sample from right kidney and diagnosed the specimen as SRCC histopathologically. Since FNA samples were similar to the SRCC, the right masseter region was predicted to be metastatic tumor from the SRCC of right kidney. Although the patient underwent systemic chemotherapy for SRCC with several anticancer agents, such as sunitinib, gemcitabine, and doxorubicin for SRCC, he died of respiratory failure 10 months after the initial chemotherapy.