[Precursor lesions of pancreatobiliary cancer]

[Surgical treatment of distal cholangiocarcinoma]

Distal cholangiocarcinoma accounts for about 20% of bile duct cancers, representing the third most common tumor entity among periampullary cancers, along with adenocarcinoma of the pancreas and carcinomas of the papilla of Vater. Precise diagnostics of tumor localization and exact knowledge of tumor-specific growth patterns are crucial for successful surgery. When planning the surgical procedure, the differential diagnosis of central bile duct cancer (Bismuth type I) or middle bile duct carcinoma must be considered. Although benign periampullary bile duct stenosis occurs in only 5% of cases, the presence of immunoglobulin G4-associated cholangitis (IAC) should be excluded in doubtful cases. Basically, in the presence of a distal cholangiocarcinoma, partial pancreatoduodenectomy is indicated analogous to the procedure for ductal adenocarcinoma of the pancreatic head. The 5‑year survival after resection is 20-25% and therefore comparable to adenocarcinoma of the pancreas. Local resection of middle bile duct carcinoma is no longer recommended due to inadequate surgical radicality. To date, perioperative treatment for downsizing does not play a relevant role for surgical treatment of distal cholangiocarcinoma. In the presence of a distal cholangiocarcinoma primary surgery with the aim of a R0 resection is the standard treatment of choice.

[Cholangiocarcinoma-diagnosis, classification, and molecular alterations]

BACKGROUND

The entity cholangiocarcinoma comprises various malignant epithelial neoplasms of different morphology, etiology, and pathogenesis.

AIM

In this review, the etiology, pathogenesis, diagnostic criteria, classification, and molecular alterations of intra- and extrahepatic cholangiocarcinomas are summarized.

MATERIAL AND METHODS

This review is based on the currently available literature and personal knowledge.

RESULTS AND DISCUSSION

Cholangiocarcinomas are morphologically and molecularly diverse neoplasms that can develop ubiquitously in the biliary tract. Since there is a significant histological and immunohistochemical overlap with frequent liver metastases, a definite diagnosis can often only be rendered in the clinical context. Cholangiocarcinomas are subclassified into intrahepatic (iCCA), perihilar (pCCA), and distal (dCCA) tumors according to macro-anatomical criteria. Recent studies show that there are distinctive molecular differences in particular between iCCA and extrahepatic CCA (eCCA, including pCCA and dCCA). In addition, morphologically well-characterized precursor lesions have been identified, which in various frequencies can be assigned not only to the anatomical classification, but also to certain etiologies. An exact classification is therefore essential, especially with regard to the development of innovative, targeted therapeutic approaches.

Pyloric gland adenoma of the cystic duct with malignant transformation: report of a case with a review of the literature

Background

Pyloric gland adenoma consists of closely packed pyloric-type glands lined by mucus-secreting cells. To date, approximately 230 cases have been reported, mostly of gastric localization with a tumour size up to 3.5 cm and a mean age of occurrence around 70 years. Adenocarcinoma develops in about 40% of cases and may be difficult to detect due to relatively mild nuclear atypia.

Case presentation

We present the first case of a pyloric gland adenoma of the cystic duct in a 62-year-old male patient and demonstrate the clinicopathologic characteristics, including radiographic, molecular, and cytogenetic findings. The 2 cm-tumour developed in the cystic duct and protruded into the hepatic and common bile duct. On microscopic examination, it displayed closely packed pyloric-type glands, and focal architectural distortion with mild nuclear atypia. Immunohistochemically, it expressed MUC1, MUC5AC, MUC6 and p53, but not MUC2 and CD10. The Ki67-proliferation index was 25%. Furthermore, high-grade intraepithelial neoplasia was observed in the surrounding bile duct. We detected chromosomal gains at 7p, 7q11q21, 15q, 16p, 20, losses at 6p23pter, 6q, 18, and amplifications at 1q and 6p21p22 in the pyloric gland adenoma by comparative genomic hybridization. A KRAS codon 12 mutation (c.35G>T; p.G12V) was detected in the pyloric gland adenoma and in the adjacent dysplasia by sequencing analysis. The diagnosis of pyloric gland adenoma was established with transition into well-differentiated adenocarcinoma and high-grade biliary intraepithelial neoplasia.

Conclusion

Pyloric gland adenoma evolving in the cystic duct is a rare differential diagnosis of obstructive bile duct tumours. Other premalignant bile duct lesions may be associated. Due to the risk of developing adenocarcinoma, surgical resection should be performed.