An intraductal papillary neoplasm of the bile duct mimicking a hemorrhagic hepatic cyst: a case report

Abstract

An intraductal papillary neoplasm of the bile duct is a biliary, epithelium-lined, cystic lesion that exhibits papillary proliferation and rarely causes large hemorrhagic cystic lesions. Here, we report a case of an intraductal papillary neoplasm of the bile duct mimicking a hemorrhagic hepatic cyst in a middle-aged man with large hemorrhagic hepatic cysts who experienced abdominal pain and repeated episodes of intracystic bleeding. Following portal vein embolization, extended right hepatic lobectomy was performed, and intraoperative cholangiography revealed communication between the intracystic space and the hepatic duct. Although histological studies revealed that the large hemorrhagic lesion was not lined with epithelium, the surrounding multilocular lesions contained biliary-derived epithelial cells that presented as papillary growths without ovarian-like stroma. A diagnosis of oncocytic-type intraductal papillary neoplasm of the bile duct was made, and we hypothesized that intracystic bleeding with denudation of the lining epithelial cells might occur as the cystically dilated bile duct increased in size. Differential diagnosis between a hemorrhagic cyst and a cyst-forming intraductal papillary neoplasm of the bile duct with bleeding is difficult. However, an intraductal papillary neoplasm of the bile duct could manifest as multilocular hemorrhagic lesions; therefore, complete resection should be performed for a better prognosis.

Figure 1

Imaging study. (a) Contrast-enhanced computed tomography scan showing the large cystic lesion (arrowhead) and surrounding small cystic lesions (arrow). (b) Non-enhanced computed tomography scan illustrating high-density components (arrow) in the low-density cystic fluid. (c) Abdominal ultrasonography scan showing mural nodules in the large cystic lesion (arrow). (d) T2-weighted sequences on magnetic resonance imaging illustrating large (arrowhead) and small cystic lesions (arrow).

Figure 2

Intraoperative cholangiography illustrating communication between the hepatic duct and the intracystic space (arrow).

Figure 3

Gross appearance and histology of the resected section. (a) The cut surface showing a large cystic lesion with a thickened wall and a hematoma. Boxed areas correspond to the areas shown in b and c. (b) On histology, the large cystic lesion was occupied by a hematoma and not lined with epithelial cells (hematoxylin and eosin stain). (c) Small multilocular lesions around the large cystic lesion were lined with epithelial cells (hematoxylin and eosin stain). (d) Magnified view of the image in c. These epithelial cells contained abundant eosinophilic cytoplasm and round nuclei, presenting as papillary growths without ovarian-like stroma (hematoxylin and eosin stain).