Branch duct intraductal papillary mucinous neoplasms of the pancreas (BD-IPMN) without malignant features rarely developed into invasive cancer. However, invasive cancer is aggressive once an invasive change occurs. We report three cases of invasive cancers which developed in patients with BD-IPMN and they showed grave clinical courses. All patients were diagnosed with BD-IPMN < 3 cm without malignant features on imaging. Invasive cancer was detected at 2.5 years, 3.0 years, and 4.0 years after BD-IPMN detection in each patient. The intervals of invasive cancer and the last follow-up were 9 months, 3 years, and 1.5 years in the three patients, respectively. All patients were diagnosed with locally advanced pancreas invasive cancers and were treated with palliative chemotherapy or conservative management. The patients died at 3 months, 9 months, and 10 months after the diagnosis of invasive cancers, respectively. We report three cases of invasive cancer developed in BD-IPMN patients and followed fatal courses.

담도 과오종과 선천성 간섬유증은 태생기에 간판 기형에 의해 생기는 섬유 낭성 질환에 속한다. 담도 과오종은 증상 을 유발하지 않고 우연히 발견되는 질환이지만, 선천성 간섬 유증은 25%에서 담관염이 발생하고 증상이 발생하면 항생 제 투여부터 수술까지 적극적 치료가 필요하다. 저자들은 복부 영상 소견으로 담도 과오종으로 진단하고 경과 관찰하던 64세 남자가 2년간 반복적인 담관염이 발생한 원인을 찾기 위해 시행한 간 생검에서 담도 과오종과 선천성 간섬유증이 병합된 것으로 진단한 증례를 경험하여 문헌고찰과 함께 보고한다.