Atypical Bile Duct Adenoma, Clear Cell Type

Abstract

A variable proportion of bile duct adenomas of the liver are still confused with metastatic well-differentiated adenocarcinoma by surgeons and pathologists. We present here three examples of previously undescribed primary hepatic bile duct tumors that were composed almost entirely of clear cells that closely mimicked metastatic renal cell carcinoma. They were interpreted as atypical bile duct adenomas and occurred in two males and one female whose ages ranged from 25 to 64 years. All three tumors were incidental findings and measured from 0.8 to 1.1 cm. The clear neoplastic cells showed mild nuclear atypia and no mitotic activity. They were arranged in tubules and nests that focally infiltrated the hepatic parenchyma. For comparison, a case of clear cell cholangiocarcinoma and 13 conventional bile duct adenomas were examined. The clear cell cholangiocarcinoma was larger (6.0 cm) and had the tubular pattern of conventional cholangiocarcinoma and an abundant desmoplastic stroma. The clear cells of this tumor exhibited greater nuclear atypia and increased mitotic activity. All three atypical bile duct adenomas expressed cytokeratin (CK) 7, p53 protein, epithelial membrane antigen (EMA), and carcinoembryonic antigen (CEA); they were negative for CK20, vimentin, Hep Par 1, chromogranin, and prostatic specific antigen (PSA) and exhibited less than 10% of Ki-67-positive nuclei. One atypical bile duct adenoma displayed luminal immunoreactivity for villin. With the exception of Ki-67 reactivity, the 13 conventional bile duct adenomas and the clear cell cholangiocarcinoma had essentially a similar immunohistochemical profile as that of the atypical clear cell bile duct adenomas. The absence of an extrahepatic primary tumor, the histologic features, the immunohistochemical profile, and the fact that all patients are symptom-free 2 months to 18 years after wedge liver biopsy support the interpretation of atypical clear cell bile duct adenoma. The differential diagnosis with clear cell hepatocellular carcinoma and metastatic clear cell carcinomas is discussed.

Bile duct adenoma: a case report and literature review

“…Further, the variation of the hyaline cell formation is very similar to renal-cell carcinoma. However, scholars, such as Saavedra [7], believe that the positive CK7, EMA, and CEA stains and negative Ki67 and CK20 stains can be helpful for differentiation.…”

Cytopathologic, Histopathologic, and Immunohistochemical Features of Intrahepatic Clear Cell Bile Duct Adenoma: A Case Report and Review of the Literature

“…Only three clear cell bile duct adenomas have been reported previously in the literature [2]. As such, experience with this entity is very limited.…”

“…As such, experience with this entity is very limited. In their report, Albores-Saavedra et al [2] described intrahepatic clear cell bile duct adenomas as small, subcapsular tumors ranging in size from 0.8 cm to 1.1 cm. Microscopically, the tumors are composed of clear cells with minimal cytologic atypia with focal infiltration into the adjacent liver parenchyma.…”

“…To date, only 3 cases have been reported in the literature [2]. In this report, a case of intrahepatic clear cell bile duct adenoma with background of marked hepatic steatosis is presented.…”

Intrahepatic clear cell cholangiocarcinoma - An uncommon histologic subtype: case report and literature review

“…Recently, a clear cell variant has been described. This histologic subtype is very rare, and so far only nine cases of intrahepatic clear cell cholangiocarcinoma have been reported (2)(3)(4)(5)(6)(7)(8). This entity is characterized by cells with a clear cytoplasm and well-defined cell membrane, residing within a highly vascularized stroma.…”