Infectious Hepatic Cyst: An Underestimated Complication.

Objective An infectious hepatic cyst (IHC) is a hepatic cyst complicated with secondary infection and is generally assumed to be rare. However, we have experienced no small number of patients with IHC in recent clinical practice. We therefore examined the incidence and clinical characteristics of IHC. Methods The medical records of patients with IHC who were hospitalized at our institution between January 2012 and December 2016 were retrospectively reviewed. Their demographic factors, biochemical, bacteriological, imaging, and treatment results were explored and compared with those of patients with pyogenic liver abscess (PLA). Patients Twelve patients with IHC and 39 with PLA were identified. Results The IHCs were significantly larger in diameters than the PLAs, and patients with IHCs tended to be older and more often women than those with PLAs. IHCs showed characteristic imaging features, including heterogeneous contents with occasional fluid-debris levels, a thickened cystic wall with rim enhancement, perilesional edema and hyperaemia. Patients with IHCs had a significantly shorter hospital stay than those with PLAs. Conclusion Physicians should note that IHCs are not rare. A careful imaging evaluation can suggest an IHC, and the timely aspiration of the content can lead to an accurate diagnosis. The cystic wall may keep the infectious material confined within the IHC, resulting in the observed good treatment outcome with catheter drainage.