Small-duct intrahepatic cholangiocarcinoma (iCCA) appears to be more frequently associated with exposure to asbestos than large-duct iCCA, according to a pilot study published in Scientific Reports. This finding suggests that asbestos fibers might represent a parenchymal risk factor for iCCA. “This pilot study must be confirmed by further case-control studies or large independent cohorts,” the authors wrote.

Asbestos exposure seems to be a possible risk factor for the development of iCCA. However, the potential link between asbestos exposure and iCCA morphology has not been explored. 

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In the present study, a team of researchers from Italy investigated this possible connection. They prospectively recruited 40 patients with surgically resected iCCA and assessed their asbestos exposure using the Italian National Mesothelioma Register questionnaire.

Of these 40 patients, 32 had small-duct iCCA and the remaining 8 had large-duct iCCA.

Of the 32 patients with small-duct iCCA, 5 had definite or probable occupational exposure to asbestos. Of the 8 patients with large-duct iCCA, none were definitely or probably exposed to occupational asbestos.

Sixteen patients with small-duct iCCA and 3 patients with large-duct iCCA had occupational, familial, or environmental asbestos exposure.

Finally, 11 patients with small-duct iCCA and 5 patients with large-duct iCCA were unlikely to have been exposed to asbestos. 

“This study reinforces the putative association between asbestos exposure and iCCA,” the researchers wrote, “suggesting for the first time that the exposure to asbestos might be more likely to be related to the small-duct histological subtype of iCCA than to the large-duct subtype.”

CCA is a group of rare malignant tumors affecting the biliary tract. The disease can be intrahepatic or extrahepatic. Extrahepatic CCA can be distal or perihilar. iCCA has recently been divided into 2 types, small-duct iCCA and large-duct iCCA.


Vasuri F, Deserti M, Corradini AG, et al. Asbestos exposure as an additional risk factor for small duct intrahepatic cholangiocarcinoma: a pilot study. Sci Rep. Published online February 13, 2023. doi:10.1038/s41598-023-27791-1