Imaging findings of biliary hamartomas

Abstract

Aim: To evaluate the imaging findings of biliary hamartomas (von Meyenburg complexes, VMCs) and discuss the differential diagnosis with other related diseases.

Methods: Imaging findings of biliary hamartomas on ultrasonography (US), computed tomography (CT), magnetic resonance imaging (MRI), MR cholangiopancreatography (MRCP)and hepatobiliary scintigraphy were retrospectively analyzed in six patients.

Results: On ultrasound images, five of the six cases showed multiple small hyper- and hypo-echoic lesions with comet-tail echoes, especially when magnified by US with the usage of zoom function. In all the six cases, multiple tiny hypodense lesions less than 10 mm in diameter were revealed as scattered throughout the liver with no enhancement on CT. These tiny lesions were demonstrated to be hyper- and hypo-intensity on T2- and TI-weighed images, respectively, in three patients who underwent MRI examinations. MRCP was performed in two patients, and clearly showed multiple tiny irregular- and round-shaped hyper-intensity lesions. MRCP and hepatobiliary scintigraphy showed normal appearances of intra- and extra-hepatic bile ducts in two and one patients, respectively.

Conclusion: Imaging modalities are useful in the diagnosis and differential diagnosis of VMCs. A correct diagnosis might be obtained when typical imaging findings are present even without a histological confirmation.

Figure 1

A 51-year-old man with VMCs. A: B-mode US showed multiple small hyper- and hypoechoic lesions less than 10 mm in diameter with multiple comet-tail echoes; B: On plain CT, multiple small hypodense lesions scattered in the whole liver especially in the subcapsular area of posterior segment of the right liver lobe; C: On enhanced CT, the small lesions became well delineated when compared with that on plain CT. No enhancements were noted in these lesions; D: T2-weighed image revealed multiple small lesions with high signal intensity; E: After gadolinium administration on T1-weighed image, hypo-intensity of the lesions was clearly shown without contrast medium enhancement; F: Hepatobiliary scintigraphy by using 99mTC-PMT showed normal appearances of biliary system without pooling areas; G: On histology, multiple irregularly dilated bile ducts lined by a single layer of cubic epithelium were shown.

Figure 2

A 72-year-old man with VMCs. A: On B-mode US, multiple small hyperechoic lesions were shown, while hypo-echoic lesions were not evident on the conventional scanning plan. However, with the use of zoom function, the hypoechoic lesion with comet-tail echo was clearly shown (arrows); B: On MR cholangiopancreatography, multiple small hyper-intensity lesions were revealed except for the demonstration of normal intrahepatic and extrahepatic bile ducts. In addition, several small cysts in the right kidney were also shown.

Figure 3

A 44-year-old man with VMCs. A: B-mode US scan with routine depth showed a vague image of multiple small hyper- and hypoechoic lesions. When magnified by using zoom function, the tiny hypoechoic lesion and the comet-tail echo were clearly seen (arrows); B,C: Multiple tiny hypodense lesions were displayed more conspicuously on enhanced CT (C) than on plain CT (B), and no enhancements were found in the lesions (C); D,E: the lesions.