Two Cases of Hepatic Cystic Neoplasm and Cyst-Adjacent Hepatocellular Carcinoma Diagnosed with Ultrasonography

Ultrasonography is the primary recommended modality for the diagnosis of hepatic cystic lesions and has the advantages of being harmless to patients and allowing real-time visualization. In this report, two cases are presented in which ultrasonography played a supportive diagnostic role but had inherent blind spots for detecting hepatic cystic lesions and adjacent malignant changes. In the first case, a detailed clinical history initially suggested drug-induced liver injury rather than mechanical biliary obstruction. However, follow-up ultrasonography revealed features inconsistent with a simple cyst, prompting a change in the therapeutic approach toward drainage and surgery. In the second case, despite the cystic lesion being readily visible on ultrasonography, a silent hidden lesion located entirely within the area of posterior acoustic enhancement almost led to a missing diagnosis. These observations underscore the need to be thoroughly familiar with the characteristics of hepatic cysts while maintaining a cautious and meticulous approach to their evaluation.