The prevalence and natural history of hepatic cysts examined by ultrasound: a health checkup population retrospective cohort study

The prevalence of hepatic cysts in the general population and their natural history are largely unknown. This study aimed to assess the prevalence and natural history of hepatic cysts by investigating health checkup participants. Ultrasonographic data of health checkup participants (n = 38,842) were retrospectively evaluated to calculate its prevalence. In addition, we assessed the changes in the size and characteristics of hepatic cysts over 10 years (n = 7709). We found the prevalence of hepatic cysts was 21.9%. Older age, female sex, and presence of kidney cysts or pancreatic cysts were associated with the occurrence of hepatic cysts. Younger age, female sex, and the existence of multiple hepatic cysts were associated with cyst enlargement. Among 126 individuals who had hepatic cysts with a diameter of 30 mm or larger at the first visit, two (1.6%) required treatment. Remain 124 cases showed four patterns: 44 cases with enlargement, 47 stable, 11 regression after enlargement, and 22 regression. Hyperechoic fluid inside the cysts was observed in 54.5% (18 of 33), which was significantly higher than 6.6% (6 of 91) of the non-regression (OR = 17.0). The appearance of intracystic hyperechoic fluid by ultrasound may predict subsequent regression of the hepatic cyst.