What are the initial tests for evaluating hepatic (liver) cysts?

Initial Workup for Hepatic Cysts

Ultrasound is the first and often only test needed for evaluating hepatic cysts, with no bloodwork required for simple cysts. 1

Imaging Strategy

First-Line Test: Ultrasound

• Ultrasound should be performed as the initial diagnostic modality for all suspected hepatic cysts, with approximately 90% sensitivity and specificity for diagnosis 1
• Simple hepatic cysts appear as round or oval-shaped, anechoic lesions with sharp, smooth borders, thin walls, and strong posterior acoustic enhancement 1
• Once a simple cyst is confirmed on ultrasound, no further imaging (CT or MRI) is indicated 1

When to Advance Beyond Ultrasound

• MRI with contrast-enhanced sequences should be ordered when ultrasound shows complex features including: septations, mural thickening or nodularity, debris-containing fluid, wall enhancement, or calcifications 1
• Contrast-enhanced ultrasound (CEUS) can be used for complex cysts to identify vascularized septation or wall enhancement, which distinguishes malignant from benign lesions 1
• CT is less accurate than ultrasound and MRI for assessing cyst contents but may detect gas or calcification 1

Bloodwork Recommendations

Simple Hepatic Cysts

• No bloodwork is required for asymptomatic simple hepatic cysts, as these are benign developmental anomalies 2
• Tumor markers (CEA and CA19-9) should NOT be ordered for hepatic cysts, as they cannot reliably distinguish benign cysts from malignant lesions 2
• The EASL guidelines explicitly state with 100% consensus that CEA and CA19-9 cannot differentiate between hepatic cysts and mucinous cystic neoplasms 2

When Bloodwork IS Indicated

• If clinical features suggest infected hepatic cyst: order complete blood count and C-reactive protein (CRP) to assess for leukocytosis and inflammation 2
• Blood cultures should be obtained if systemic infection is suspected 2
• For polycystic liver disease (>10 cysts): order renal function tests (creatinine, BUN) to screen for associated autosomal dominant polycystic kidney disease (ADPKD) 2

Specific Diagnostic Scenarios

Polycystic Liver Disease

• Diagnosis is made when >10 hepatic cysts are present on imaging 1
• MRI is superior to ultrasound and CT for detecting small cysts, particularly in young individuals 1
• Renal function testing is mandatory to evaluate for concurrent ADPKD 2

Caroli Disease

• Magnetic resonance cholangiopancreatography (MRCP) provides the highest diagnostic accuracy for visualizing the biliary tree and confirming the diagnosis 1
• Look for the "central dot sign" representing fibrovascular bundles within dilated cystic intrahepatic ducts 1

Critical Pitfalls to Avoid

• Do not order tumor markers (CEA, CA19-9) for hepatic cysts—they are elevated in up to 50% of simple cysts and polycystic liver disease, making them non-specific 2
• Do not perform CT or MRI for simple cysts confirmed on ultrasound—this wastes resources and exposes patients to unnecessary contrast or radiation 1
• Do not rely on bloodwork to differentiate benign from malignant cystic lesions—imaging characteristics are the key discriminator 2
• For cysts with atypical features, MRI with contrast-enhanced sequences is required for definitive characterization, not bloodwork 2