# Association between ultrasound-based biliary and parenchymal intrahepatic mass-forming cholangiocarcinoma subtypes and clinicopathological features and survival

## TL;DR

This study shows that ultrasound can distinguish two types of liver cancer, which have different features and survival rates.

## Contribution

A new ultrasound-based classification of intrahepatic cholangiocarcinoma subtypes with distinct clinicopathological and prognostic differences.

## Key findings

- Biliary-type tumors show more aggressive features like higher CEA, microvascular invasion, and worse survival.
- Parenchymal-type tumors are less aggressive and have better survival outcomes.
- The ultrasound-based classification aligns with MRI-based classifications in some clinicopathological features.

## Abstract

Mass-forming intrahepatic cholangiocarcinomas (MF-ICCs) can be classified into ductal and parenchymal types using magnetic resonance imaging (MRI). We aimed to subclassify MF-ICC into biliary and parenchymal types based on ultrasound (US) findings and to investigate the differences in their contrast-enhanced ultrasound (CEUS) patterns, clinicopathologic features, and prognosis.

In this study, 141 patients who underwent US with pathologically proven MF-ICC from two hospitals were retrospectively enrolled. MF-ICCs were divided into biliary (bMF-ICCs) and parenchymal MF-ICC (pMF-ICCs) based on the signs of bile duct dilation in US images. Clinicopathological, imaging, and short-term survival data were collected from medical records and compared.

Among 141 patients (61.96 ± 10.15 years, 83 men), bMF-ICCs (33/141, 23.4%) showed significantly more CEA ≥ 5 µg/L (42.4% vs 20.2%, p = 0.01), microvascular invasion (54.5% vs 10.2%, p < 0.001), lymph node metastasis (48.5% vs 5.6%, p < 0.001), bile duct invasion (48.5% vs 5.6%, p < 0.001), and high Ki-67 expression (63.6% vs 38.9%, p = 0.01) than pMF-ICCs. Pathologically, bMF-ICCs were more inclined toward the large duct type (78.1% vs 11.7%, p < 0.001). In addition, the bMF-ICCs were usually located in the left lobe of the liver (63.6% vs 41.7%, p = 0.03). pMF-ICCs showed better overall survival than bMF-ICCs (p = 0.04).

Subclassification of MF-ICCs into biliary and parenchymal types based on US is useful for discriminating clinicopathological characteristics.

The subclassification of mass-forming intrahepatic cholangiocarcinoma (MF-ICC) into biliary (bMF-ICC) and parenchymal (pMF-ICC) subtypes using ultrasound can provide clinicopathological and prognostic information before surgery.

We subclassified mass-forming intrahepatic cholangiocarcinomas into biliary and parenchymal types using ultrasound.Biliary and parenchymal types have different clinicopathological features and postsurgical outcomes.Biliary type above and below 50 mm exhibits different unfavorable clinicopathological characteristics.Our classification has certain similarities with MRI classification in clinicopathological characteristics.

We subclassified mass-forming intrahepatic cholangiocarcinomas into biliary and parenchymal types using ultrasound.

Biliary and parenchymal types have different clinicopathological features and postsurgical outcomes.

Biliary type above and below 50 mm exhibits different unfavorable clinicopathological characteristics.

Our classification has certain similarities with MRI classification in clinicopathological characteristics.