Unexpected metastasis of intraductal papillary neoplasm of the bile duct without an invasive component to the brain and lungs: A case report

Abstract BACKGROUND: Despite an expanding number of studies on intraductal papillary neoplasm of the bile duct (IPNB), distant metastasis remains unexplained especially in cases of carcinoma in situ. In the present study, we report a rare and interesting case of IPNB without invasive components that later metastasized to lungs and brain. CASE SUMMARY: A 69-year-old male was referred to our hospital due to suspected cholangiocarcinoma. Laboratory tests on admission reported a mild elevation of alkaline phosphatase, γ-glutamyl transpeptidase, and total