What is the recommended surveillance for a small 1.9 centimeter (cm) complex cyst on the right liver?

From the Guidelines

For a small 1.9 cm complex cyst on the right liver, I recommend surveillance with follow-up imaging every 6-12 months for at least 2-3 years to monitor for any changes in size or characteristics, as suggested by the most recent guidelines 1. The initial follow-up should be at 6 months, with subsequent imaging annually if the cyst remains stable.

• Ultrasound is typically the preferred initial imaging modality due to its lack of radiation, accessibility, and lower cost, though your doctor may recommend contrast-enhanced CT or MRI for better characterization if needed.
• No medication or intervention is required at this time as most small complex liver cysts are benign. However, surveillance is important because complex cysts (those with septations, nodularity, or solid components) have a small risk of being or becoming malignant. If during follow-up the cyst shows significant growth (more than 2 mm per year), develops new concerning features, or becomes symptomatic with pain or discomfort, further evaluation with additional imaging or possibly biopsy may be warranted, as recommended by recent studies 1. You should report any new symptoms such as right upper quadrant pain, early satiety, or unexplained weight loss to your healthcare provider promptly. The 2022 KLCA-NCC Korea practice guidelines for the management of hepatocellular carcinoma 1 provide the most up-to-date recommendations for the surveillance and management of liver lesions, and should be followed in this case.
• The guidelines recommend that nodules ≥1 cm that do not meet the non-invasive diagnostic criteria of “definite” HCC should be assigned a diagnosis of “probable” HCC by applying ancillary imaging features.
• For “probable” HCC, a follow-up imaging study within 3 months or biopsy should be considered, and a treatment plan for the lesion may be determined through multidisciplinary discussion 1. In this case, since the cyst is 1.9 cm and complex, it is essential to monitor it closely for any changes that may indicate malignancy, and to follow the guidelines for surveillance and management of liver lesions 1.

From the Research

Surveillance of a Small 1.9 cm Complex Cyst on the Right Liver

• The management of complex cystic liver lesions can be challenging due to their heterogeneous nature and similar clinical and imaging characteristics 2, 3.
• Imaging modalities such as conventional ultrasound, computed tomography, magnetic resonance imaging, or contrast-enhanced ultrasound can be used to further characterize and diagnose hepatic cysts 3, 4.
• The first step in diagnosis is stratifying risk by differentiating simple and complex cysts, with features such as septae, mural consistency, calcifications, and quality of cystic fluid helping to identify complex cysts 3.
• Complex cysts include mucinous neoplasms, echinococcal cysts, hemorrhagic cysts, cystic hepatocellular carcinoma, and other rare lesions, and treatment is indicated in symptomatic cysts or those suspicious for malignant or premalignant features 3, 5.
• Contrast-enhanced ultrasound is a newer modality that offers non-invasive evaluation in real-time and can provide information about contrast enhancement of the liver and focal liver lesions almost as CT and MRI do, but in real time and without the use of ionizing radiation 4.

Diagnosis and Management

• The diagnosis and management of complex liver cysts require a comprehensive approach, including imaging modalities and fine needle aspiration (FNA) in some cases 5.
• Pre-operative differentiation of cystadenoma from cystadenocarcinoma is impossible, and surgery must be performed if a biliary cyst tumor is suspected 5.
• Multiple biliary hamartomas (von Meyenburg complex) can appear as a mixture of solid and cystic lesions and can be confused with cystic metastasis, and strong and uniform T2 hyperintensity on MRI is usually diagnostic 5.

Size and Significance

• The size of the cyst (1.9 cm) may be considered small, but the term "small" can be relative, and the significance of the cyst's size should be evaluated in the context of the individual patient's condition and the characteristics of the cyst 6.