Imaging features of intrahepatic bile duct adenoma in MRI

Intrahepatic bile duct adenoma (BDA) is a rare benign epithelial hepatic tumor, and is very easy to miss or misdiagnose. This study was to investigate the magnetic resonance imaging (MRI) findings of intrahepatic BDA and to improve the imaging understanding of the disease.

The clinical and MRI imaging data of 25 cases of intrahepatic BDA confirmed by operation and pathology were analyzed retrospectively from the aspects of tumor location, size and shape, signal characteristics and enhancement mode.

Among the 25 patients, 24 cases (96%) were single lesions, only 1 case had multiple lesions (3 lesions), a total of 27 lesions. Twelve lesions were located in the left lobe of the liver, 15 lesions were located in the right lobe of the liver, and the lesions were located under or near the hepatic capsule. The lesions were round and the size was 4 to 20 mm, with an average of 10.2 mm. In T1 weighted image (T1WI) sequence, all lesions were low or slightly low signal. In T2 weighted image (T2WI) sequence, 20 lesions were high or slightly high signal (74.1%), 4 were central equal signal peripheral ring high signal, and 3 were equal signal. In diffusion-weighted imaging (DWI) sequence, 23 lesions were high or slightly high signals (85.2%), and 4 were ring high signals. Nineteen lesions (70.4%) showed marked enhancement in the arterial phase, and the portal vein and lag phase continued to strengthen with a slightly higher or equal signal, 6 lesions (22.2%) showed mild or obvious peripheral ring enhancement in the arterial phase, and the portal vein and lag phase continued to strengthen with a slightly higher signal around the circumference and a slightly lower signal at the center. Eight cases were examined by gadolinium ethoxybenzyl diethylenetriaminepentaacetic acid (Gd-EOB-DTPA)-enhanced MRI, 7 cases were low signal in hepatobiliary phase, and 1 case was Peripheral low signal.

The MRI findings of intrahepatic BDA have certain characteristics. Careful observation and analysis are helpful to the understanding and diagnosis of the disease.