Immunohistochemistry for MUCs shows MUC1 (+)/MUC2 (−)/MUC5AC (+)/MUC6 (+) in pancreatobiliary and oncocytic types.[2,19–21] Approximately 65% of the BD-IPMNs are of gastric type.[22] However, if IPMN has a tendency towards malignant change, the histological subtypes of BD-IPMNs are usually tubular type.[23] Our case was MUC1 (+)/MUC2 (+)/MUC5AC (+) BD-IPMN, suggesting he had the pancreatobiliary type. The gene discussed is MUC5AC; the disease is Behcet disease.