Benign Epithelial Tumors and Hamartomas of the Biliary Tract

Intrahepatic Biliary Proliferations: Histopathology and Potential Immunohistochemical Markers

“…Rather common lesions (3) with diverse names in the literature, VMC is considered a form of ductal plate malformation (4)(5)(6) , sometimes related to congenital cystic liver disease (7) and to recurrent cholangitis (8) . The patients are usually asymptomatic, presenting as solitary (9) or multiple nodules (1,4) , or even as a multicystic lesion (10) . Recently, an atypical presentation of rapidly enlarging VMC was described (11) .…”

“…Macroscopically, the lesions are typically subcapsular and well defined nodules (4) , usually less than 0.5 cm (5) , rarely forming a cyst (2) . The VMC is composed of branching irregular bile ducts with uniform cytological appearance (5) , embedded in a fibrous and hyalinized stroma (1,4,6) , with variable amounts of lymphocytes (4) (FIGURE 1). The lumina contain amorphous material or inspissated bile (5,12,13) .…”

“…BDA usually presents as a single lesion, more frequently subcapsular, flattened, well circumscribed and not encapsulated, ranging from 1 to 20 mm (4) .…”

“…BDA is composed of uniformly shaped and spaced tubules, branching and densely packed (4) ; without evident atypia or mitosis (1,5) , and their nuclei are lighter than in normal bile duct (4) . These tubules may contain mucin and may be found in preexisting portal tracts (1) .…”

“…Variable amounts of stroma, with sparse lymphocytic cells, is more pronounced at the margins (27) . Microcalcification (31) and hyalinization (4) are occasionally found.…”