Von Meyenburg complexes (VMCs), also known as biliary hamartomas, were first described by Hanns von Meyenburg in 1918 and are generally considered as a benign form of embryonic ductal plate malformation.
VMCs typically consist of bile duct remnants involving small intrahepatic biliary ducts embedded within fibrous stroma often containing inspissated bile.
The incidence of VMCs is low, with a reported range from 0.35% in liver biopsy specimens 2 to 5.6% on autopsy series.
VMCs are usually diagnosed on imaging when there are multiple small cystic lesions in the liver.
VMCs are generally considered as incidental findings, but can mimic hepatic metastases and other clinically significant entities such as granulomas and multiple liver abscesses.
Grossly, VMCs appear as small subcapsular or parenchymal solid tan-white 1 to 5mm nodules.
Liver biopsy: Microscopically, VMCs appear as tiny lesions consisting of malformed bile ducts of varying caliber in a densely collagenized stroma. The ductal structures range from being narrow to markedly dilated, are often irregular in shape, and frequently contain inspissated bile. These are usually lined by a single layer of cuboidal, columnar, or flat epithelium that lacks any cytological atypia. The connective tissue stroma in which the ducts are embedded is more dense compared with the normal portal tracts and often appears hyalinized. Variable amount of calcification can be seen.
Clinical significance: VMCs are often incidental findings on histology and are invariably asymptomatic. Grossly, they mimic granulomas or metastasis. Their distinction from granulomas is not an issue on histology. The presence of multiple VMCs may prompt careful scrutiny for coexisting cholangiocarcinoma and to look for cystic kidney disease.
References
Guo Y, Jain D A, Weinreb D. von Meyenburg complex: current concepts and imaging misconceptions. J Comput Assist Tomogr. 2019;43:846-851.
Lorenzon L, Ziparo V. von Meyenburg complexes mimicking liver metastases. Hepatology. 2011;54:734-5.
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