Squamous cell carcinoma antigen (SCC-Ag) is a well-established tumor marker for monitoring recurrence of squamous cell carcinoma of the cervix. However, serum levels of SCC-Ag could be elevated by some benign conditions not to speak of squamous cell malignancies other than cervical carcinoma. Sinonasal inverted papilloma is one of benign tumor which may elevate serum SCC-Ag level. We experienced a case of cervical carcinoma patient whose serum level of SCC-Ag was not normalized in spite of combination chemotherapy until surgical removal of maxillary inverted papilloma detected by PET/CT.