Abstract
A 58-year-old man with neurofibromatosis type 1 (NF1) showed mild liver dysfunction. Abdominal ultrasonography and contrast-enhanced CT scan demonstrated a papillary tumor in the dilated segmental bile duct B3 of the liver. ERCP showed an elevated lesion within the cystically dilated bile duct B3 and a subsequent peroral cholangioscopy-guided tumor biopsy demonstrated mucin-producing papillary neoplasm, being compatible with the diagnosis of intraductal papillary neoplasm of the bile duct (IPNB). Laparoscopy-assisted left hepatectomy was then performed. Histopathologically, the tumor was a well-differentiated papillary adenocarcinoma with accumulation of mucin and tumor cells were confined to the mucosal layer of the bile duct without invasion to the basement membrane. Subtype analysis of the IPNB was the pancreatobiliary type and an immunohistochemical expression of neurofibromin in the tumor tissue was not seen. Although patients with NF1 have an increased risk to develop tumor throughout the gastrointestinal tract, this is the first case of IPNB in patients with FN1 in Japan.
