What monitoring is required for biliary hamartomas (benign liver tumors)?

From the Guidelines

Biliary hamartomas do not require routine monitoring, as they are benign liver lesions with a low risk of malignant transformation, and the current evidence does not support regular follow-up imaging for asymptomatic patients 1. When diagnosed, biliary hamartomas are typically found to be stable over time, and patients do not require any specific medication, dietary changes, or activity restrictions.

Key Considerations

• Biliary hamartomas are developmental malformations consisting of dilated bile ducts surrounded by fibrous stroma, and they do not have malignant potential in the vast majority of cases.
• The incidence of malignancies associated with biliary hamartomas is unclear, but it is considered to be very low, with some studies suggesting a possible association with intrahepatic cholangiocarcinoma 1.
• Asymptomatic patients with biliary hamartomas and concomitant liver diseases should have a follow-up that is determined by the primary liver disease, rather than the biliary hamartomas themselves 1.

Clinical Approach

• Once diagnosed through imaging studies such as ultrasound, CT, or MRI, and confirmed to be biliary hamartomas, routine follow-up imaging is generally unnecessary, unless there is uncertainty about the diagnosis or atypical features are present 1.
• Patients with biliary hamartomas should be counseled on the benign nature of these lesions, and the low risk of malignant transformation, to avoid unnecessary anxiety or interventions 1.

From the Research

Monitoring of Biliary Hamartomas

• Biliary hamartomas can be monitored using various imaging modalities, including ultrasonography, computed tomography (CT), magnetic resonance imaging (MRI), and MR cholangiopancreatography (MRCP) 2, 3, 4, 5.
• Ultrasonography can detect suspected biliary hamartomas, but may occasionally result in mistakes, and follow-up examinations are necessary 3.
• CT is effective in the diagnosis of biliary hamartomas, but MRI is considered the best choice for further diagnosis due to its ability to provide detailed images of the lesions 3, 4, 5.
• MRI can show characteristic features of biliary hamartomas, including high signal intensity on T2-weighted images and thin rim enhancement on gadolinium-enhanced images 4, 5.
• MRCP can clearly show multiple tiny irregular- and round-shaped hyper-intensity lesions, and hepatobiliary scintigraphy can show normal appearances of intra- and extra-hepatic bile ducts 2.

Imaging Features

• Biliary hamartomas typically appear as multiple small hyper- and hypo-echoic lesions with comet-tail echoes on ultrasonography 2.
• On CT, they appear as multiple tiny hypodense lesions less than 10 mm in diameter, with no enhancement 2.
• On MRI, they appear as high signal intensity lesions on T2-weighted images, with thin rim enhancement on gadolinium-enhanced images 4, 5.
• Lesions can be solitary or multiple, and range in diameter from 0.5 to 1.5 cm 5.

Diagnostic Considerations

• Biliary hamartomas can be difficult to diagnose due to their similarity to other liver lesions, such as metastases and small hepatocellular carcinoma (SHCC) 6, 4.
• Pathology is imperative for correct diagnosis of biliary hamartomas, especially when imaging findings are atypical 6.
• Knowledge of MR imaging findings of biliary hamartomas is helpful for a prompt and correct diagnosis, avoiding unnecessary invasive procedures and/or an excessive number of radiological investigations 4.