CP and pachyonychia congenita: As to CA 19-9 levels, their median values were significantly higher (p < 0.001) in patients with IPMN (17.9 U/ml; Q1–Q3 = 5.1–143.9) and CP (17.4 U/ml; Q1–Q3 = 10.1–28.5) compared with either HS (4.3 U/ml; Q1–Q3 = 2.4–7.9) or PC patients (299 U/ml; Q1–Q3 = 70.1–1615).