Biliary hamartomas: Solitary and multiple lesions shown on current MR techniques including gadolinium enhancement

The purpose of this study was to describe the magnetic resonance (NIR) imag ing features of biliary hamartomas on T1- and T2-weighted and gadolinium-en hanced sequences, and to correlate these findings with histopathology. MR i maging findings in four patients with pathologically proved biliary hamarto mas are described. In all patients, MR imaging sequences, including T1- and T2-weighted and early and late gadolinium-enhanced images, were retrospect ively evaluated for the size, morphology, signal intensity, and enhancement pattern of the lesions, Correlation was made between the MR imaging findin gs and histopathology, Biliary hamartomas ranged in diameter from 0.5 to 1. 5 cm, Lesions were solitary in one patient and numerous in three patients. In all patients, the lesions were low signal on T1-weighted images and high signal and well-defined on T2-weighted images and demonstrated thin rim en hancement on early post-gadolinium images that persisted on late post-gadol inium images. No appreciable central enhancement of the lesions was observe d, At histopathology, the lesions were composed of cystic spaces and fibrou s stroma, Lesions showed compressed liver parenchyma surrounding the lesion s (three cases) and inflammatory cell infiltrate (one case), which correlat ed with the rim enhancement on the gadolinium-enhanced MR images. Most of t he biliary hamartomas in our small series were less than 1 cm in diameter a nd of high signal intensity on T2-weighted images, and had a thin rim of en hancement on early and fate post-gadolinium images. The imaging features we re explainable by the underlying histopathology, In patients with known mal ignancy, caution should be exercised not to misinterpret these lesions as m etastases due to the presence of thin rim enhancement. (C) 1999 Wiley-Liss, Inc.