A Case of Primary Sinonasal Yolk Sac Tumor.

Yolk sac tumor (YST) is a rare and highly malignant germ cell tumor that is extremely rare in the nasal region. Herein, we present a case of biopsy-proven nasal YST admixed with transitional cell carcinoma in a 58-year-old woman. Complementary F-FDG PET/CT revealed the only FDG-avid mass in the right nasal cavity. This case indicates that YST could occur in the nasal region primarily, and F-FDG PET/CT is a useful tool to distinguish between primary and metastatic lesions.