What is the workup for simple and complex liver cysts?

Workup of Simple and Complex Liver Cysts

Ultrasound should be the first imaging modality used to diagnose simple hepatic cysts and polycystic liver disease, while hepatic cysts demonstrating complex features require further evaluation using additional imaging such as MRI. 1

Initial Diagnostic Approach

Simple Liver Cysts

• First-line imaging: Ultrasound 1, 2
  • Typical findings: anechoic, round or oval-shaped with sharp and smooth borders, thin walls, and strong acoustic posterior enhancement 1
  • Once diagnosed on ultrasound, CT and MRI are generally not indicated for further characterization 1
  • Key advantage: widely available, inexpensive, and no radiation exposure 1

Complex Liver Cysts

• Definition: Cysts with irregular walls, septations, calcifications, mural thickening or nodularity, debris-containing fluid, hemorrhagic or proteinaceous contents, fluid levels, wall enhancement, or associated bile duct dilatation 1, 3
• Required additional imaging: MRI or CT 1
  • MRI is preferred for characterization of complex cysts 1
  • MRI protocol should include:
    • Half-Fourier single-shot turbo spin echo sequences
    • T1 and T2-weighted sequences
    • Contrast-enhanced sequences 1

Specific Diagnostic Criteria and Workup

Key Elements in Description of Hepatic Cysts

1. Number of lesions: solitary vs. multiple 1
2. Architecture: simple vs. complex 1

For Complex Cysts

• MRI should be used to characterize hepatic cysts with worrisome features 1
• Worrisome features include a combination of >1 major and >1 minor features as defined in clinical guidelines 1
• Contrast-enhanced ultrasound may be helpful to identify malignant cystic lesions by demonstrating vascularized septation or wall enhancement 1, 3

For Biliary Hamartomas

• MRI with heavily T2-weighted sequences and MR cholangiography sequences is the diagnostic modality of choice 1
• Typical appearance: small innumerable T2 hyperintense cystic lesions scattered throughout hepatic parenchyma without communication with bile ducts ("starry sky" appearance) 1

For Polycystic Liver Disease (PLD)

• Current diagnosis is made in the presence of >10 hepatic cysts 1
• MRI or CT is useful to evaluate:
  • Distribution of cysts within the liver
  • Presence of hepatic or portal vein compression
  • Volume of non-affected liver 1

Laboratory Testing

• Tumor markers (CEA and CA19-9) in blood or cyst fluid cannot be used to discriminate between hepatic cysts and mucinous cystic neoplasms 1
• Tumor-associated glycoprotein 72 (TAG-72) in cyst fluid may help distinguish between simple hepatic cysts and mucinous cystic neoplasms 1

Management of Complications

For Suspected Cyst Infection

• Diagnostic criteria:
  • Definite: neutrophil debris and/or microorganisms in cyst aspirate 1
  • Likely: based on clinical, biochemical, and radiological parameters 1
• Consider contrast-enhanced CT, MRI, or 18FDG PET-CT when infection is suspected 1

For Suspected Cyst Hemorrhage

• Ultrasound (showing sediment or mobile septations) and/or MRI (heterogeneous and intense signal on both T1 and T2-weighted sequences) may be used 1
• CT is not recommended to diagnose cyst hemorrhage 1

Follow-up Recommendations

• It is not recommended to follow asymptomatic patients with simple hepatic cysts, biliary hamartomas, or peribiliary cysts 1
• Routine follow-up with imaging after aspiration sclerotherapy or surgical procedures for hepatic cysts is not recommended 1
• If symptoms occur in patients with simple hepatic cysts, ultrasound should be the first diagnostic modality used 1

Common Pitfalls to Avoid

1. Unnecessary surgery: Radiologic reporting of simple hepatic cysts as possible biliary cystadenomas can lead to unnecessary surgical interventions 4
2. Overreliance on tumor markers: CEA and CA19-9 cannot reliably differentiate between benign cysts and mucinous cystic neoplasms 1
3. Inappropriate ablation therapy: Laparoscopic cyst unroofing is generally more effective and safer than ablation therapy for symptomatic simple liver cysts 5
4. Unnecessary follow-up imaging: Asymptomatic simple cysts do not require routine follow-up 1, 2

By following this evidence-based approach to the workup of liver cysts, clinicians can accurately diagnose these lesions while minimizing unnecessary procedures and follow-up imaging.