Pathological aspects of mucinous cholangiocarcinoma: A single‐center experience and systematic review

Abstract

Cholangiocarcinoma is a malignant neoplasm originating from the biliary epithelium. Its incidence is highest in Southeast Asia, especially in Thailand. Mucinous intrahepatic cholangiocarcinoma (mucinous iCCA), characterized by an abundant extracellular mucin pool accounting for at least 50% of total tumor volume, is an extremely rare variant of such malignancy and is notorious for rapid progression and dismal prognosis. We conducted an 11‐year retrospective analysis of resected mucinous iCCAs from our institution with a systematic review on mucinous iCCAs and combined hepatocellular‐mucinous cholangiocarcinoma (cHCC‐mCCA). There were four resected mucinous iCCA specimens at our institution (prevalence = 0.5%). Most of the patients were male. The clinicopathological characteristics were variable. The diagnosis of mucinous iCCAs could not be rendered without pathological evaluation. Either intraductal papillary neoplasm or biliary intraepithelial neoplasia was present in three out of four cases. One patient passed away at 11 months following liver resection. A total of 19 mucinous iCCAs and four cHCC‐mCCAs from previously published literature were analyzed. The 1‐year mortality rate of mucinous iCCAs from our series and published literature is 35%. The present study confirmed that mucinous iCCA is an exceedingly uncommon variant of iCCA. The differential diagnoses include metastatic carcinoma with mucinous component and cHCC‐mCCA.

Rare histotypes of epithelial biliary tract tumors: A literature review

“…Mucinous cholangiocarcinoma (mCCA) is a rare variant of CCA. It represents 0.5 % of intrahepatic cholangiocarcinoma (Laohawetwanit and Klaikaew, 2020). This rare BTC is more common in males, with a median age of 59.3 years at diagnosis (range 40 years-82 years).…”

“…This rare BTC is more common in males, with a median age of 59.3 years at diagnosis (range 40 years-82 years). The pathogenesis is unknown, but some papers report a possible association with a history of the chronic bilio-hepatic disease, like choledocholithiasis and primary sclerosing cholangitis (Laohawetwanit and Klaikaew, 2020;Sasaki et al, 1995). So far, only one case was described of a patient with a genetically determined syndrome, as the case of a patient with mucinous cholangiocarcinoma associated with Muir-Torre syndrome (Vernez et al, 2007).…”

“…MCCA is characterized by a plentiful extracellular mucin pool representing at least 50 % of total tumor volume (Laohawetwanit and Klaikaew, 2020) with a gelatinous cut surface. Similar to large duct-iCCA, it arises from intraductal papillary neoplasms of the bile duct or mucinous cystic neoplasms, yet it mainly does not arise on precancerous lesions (Laohawetwanit and Klaikaew, 2020).…”

“…MCCA is characterized by a plentiful extracellular mucin pool representing at least 50 % of total tumor volume (Laohawetwanit and Klaikaew, 2020) with a gelatinous cut surface. Similar to large duct-iCCA, it arises from intraductal papillary neoplasms of the bile duct or mucinous cystic neoplasms, yet it mainly does not arise on precancerous lesions (Laohawetwanit and Klaikaew, 2020). Mucinous cholangiocarcinoma is usually infiltrating (Motoo et al, 1993), as favored by the frequent absence of peritumoral fibrous capsule and the intrinsic aggressiveness of tumor cells themselves, showing direct invasion of the adjacent hepatic parenchyma (Sumiyoshi et al, 2017).…”

“…Like conventional cholangiocarcinoma, especially iCCA, the mucinous neoplastic cells exhibit immunoreactivity for CK7 but not CK20 and CDX2. In addition, other stainings can be positive for MUC1, MUC2, MUC5AC and MUC6 (Laohawetwanit and Klaikaew, 2020). Unlike other gastrointestinal mucinous carcinomas, mucinous cholangiocarcinoma is usually microsatellite stable (Laohawetwanit and Klaikaew, 2020).…”