[Imaging of ciliated hepatic or biliary cysts. 4 cases]

Four patients with ciliated hepatic cysts, a rare and benign lesion, were examined between 1990 and 1994. Imaging features were compared to 12 previous cases. All lesions were revealed by US, and were hypoechoic in 3 cases, and anechoic in 1 case. All lesions were less than to 4 cm in diameter, and were well-defined, unilocular, isolated, and located in subcapsular areas, usually in the medial segment of the left lobe of the liver (3 cases). In one case, the cyst was found in the gallbladder wall. The lesions were low density on pre- and post-contrast CT scan (performed in 2 cases), strongly hyperintense on T2-weighted MR images (2 cases), and had a variable signal intensity on T1-weighted MR images. One patient underwent percutaneous guided biopsy but no diagnosis was obtained. None of the patients had preoperative diagnosis and all underwent surgery. Diagnosis was confirmed by histopathologic examination of the resected specimen. Ciliated hepatic cysts may be suspected in this study and in the literature. Diagnostic criteria are as follows: hypoechogenic mass less than 4 cm in diameter, located in the subcapsular area of the medial segment of the left lobe of the liver.