The "Dirty Liver" as a Coincidental Finding on Sonography: Sonographic Criteria for Biliary Microhamartomas of the Liver.

Objectives: Biliary microhamartomas of the liver are known as symptomless, benign, microscopic biliary duct deformations. The consistently improving quality of ultrasound technology has made it possible to visualize them, which has led to difficulty in distinguishing them from neoplastic liver alterations. The purpose of this study was to evaluate the appearance of biliary microhamartomas and their behavior on contrast-enhanced sonography.

Methods: We defined typical sonographic findings in biliary microhamartomas of the liver (1 main criterion and 3 secondary criteria). Nineteen patients were identified as have typical characteristics images of biliary microhamartomas as coincidental findings on liver sonography. All patients were included in a clinical follow-up program without histologic confirmation after they underwent risk assessment. Follow-up examinations were performed with B-mode sonographic examinations at 6, 12, and 18 months. In addition, in 15 patients, contrast-enhanced sonographic examinations of the liver were performed.

Results: None of the patients had a change in the number or size of the identifiable typical liver lesions (main criterion) after a mean follow-up period ± SD of 14.4 ± 6.5 months. There were also no alterations among the aforementioned secondary criteria in any of the participants. On contrast-enhanced sonography, the lesions of all patients showed a consistent pattern, with early arterial enrichment and persistent homogeneous contrast in the late portal venous phase.

Conclusions: The sonographic appearance of biliary microhamartomas is characteristic and typical enough that histologic confirmation is not always necessary. Follow-up examinations to monitor any developments are usually adequate.