Objective::To clarify whether the serum squamous cell carcinoma antigen (SCCA) levels of patients with inverted papilloma (IP) are different from patients with nasal polyps (NP) and rhinitis.Materials and methods::Serum SCCA levels were measured in 30 patients with IP and 30 patients with NP at one day before surgery and seven days after surgery and measured in 28 patients with rhinitis.Results::Elevated serum SCCA levels (>1.5 ng/ml) were found in 80.0% of patients in the IP group, 6.7% of patients in the NP group and 14.3% of patients in the rhinitis group, which was a significant difference. The medians of serum SCCA levels in the IP, NP and rhinitis groups were 3.9, 0.8 and 1.1 ng/ml, respectively, which was a significant difference. The SCCA level in IP group was not significantly correlated according to Krouse Staging. There was a significant difference in serum SCCA levels between the pre- and postoperative stages in the IP group, at 3.9 and 0.8 ng/ml, respectively, while in the NP group the levels were 0.8 and 1.0 ng/ml, not significantly different. With regard to the IP diagnosis in the IP and NP group based on the SCCA level (>1.5 ng/ml), sensitivity and specificity was 80.0% and 93.3%, respectively.Conclusions::The serum SCCA level in patients with IP was elevated and then it decreased after surgery. This was different from NP and rhinitis patients who mostly had normal levels, which did not change.“,”Objective::To clarify whether the serum squamous cell carcinoma antigen (SCCA) levels of patients with inverted papilloma (IP) are different from patients with nasal polyps (NP) and rhinitis.Materials and methods::Serum SCCA levels were measured in 30 patients with IP and 30 patients with NP at one day before surgery and seven days after surgery and measured in 28 patients with rhinitis.Results::Elevated serum SCCA levels (>1.5 ng/ml) were found in 80.0% of patients in the IP group, 6.7% of patients in the NP group and 14.3% of patients in the rhinitis group, which was a significant difference. The medians of serum SCCA levels in the IP, NP and rhinitis groups were 3.9, 0.8 and 1.1 ng/ml, respectively, which was a significant difference. The SCCA level in IP group was not significantly correlated according to Krouse Staging. There was a significant difference in serum SCCA levels between the pre- and postoperative stages in the IP group, at 3.9 and 0.8 ng/ml, respectively, while in the NP group the levels were 0.8 and 1.0 ng/ml, not significantly different. With regard to the IP diagnosis in the IP and NP group based on the SCCA level (>1.5 ng/ml), sensitivity and specificity was 80.0% and 93.3%, respectively.Conclusions::The serum SCCA level in patients with IP was elevated and then it decreased after surgery. This was different from NP and rhinitis patients who mostly had normal levels, which did not change.