Low-Risk vs. High-Risk Patients
The algorithm splits on two patient factors: (1) known malignancy and (2) cirrhosis or chronic liver disease placing the patient at risk for HCC.
Low-risk patient (no known malignancy, no cirrhosis)
| Finding | Recommendation |
|---|---|
| Simple hepatic cyst ≤2 cm (imperceptible wall, water density, no enhancement) | No follow-up |
| Simple hepatic cyst >2 cm | Confirm with US; no follow-up if typical |
| Hemangioma (confirmed typical appearance) | No follow-up regardless of size |
| FNH (confirmed) | No follow-up |
| Indeterminate lesion ≤1.5 cm | MRI with contrast in 6 months; if stable → no follow-up |
| Indeterminate lesion 1.5–3 cm | MRI with contrast (hepatobiliary agent preferred) |
| Indeterminate lesion >3 cm | MRI with contrast; hepatobiliary surgery referral |
| Hypervascular lesion (early enhancement, washout) | MRI with hepatobiliary agent; HCC evaluation if any cirrhosis risk |
| Calcified lesion (granuloma, calcified cyst) | No follow-up if clearly calcified and stable |
High-risk patient (known malignancy or cirrhosis)
| Finding | Recommendation |
|---|---|
| Simple hepatic cyst (atypical features) | MRI for characterization |
| Hemangioma | MRI to confirm; if confirmed → no follow-up |
| FNH | MRI with hepatobiliary agent to confirm |
| Indeterminate lesion ≤1.5 cm | Multiphasic CT or MRI; hepatology referral |
| Indeterminate lesion 1.5–3 cm | MRI or multiphasic CT; hepatology/oncology referral |
| Indeterminate lesion >3 cm | MRI + hepatology/oncology; biopsy if needed |
| Hypervascular lesion | LI-RADS system; hepatology referral |
| Calcified lesion | Clinical correlation; usually benign |
LI-RADS for Cirrhotic Patients
Use LI-RADS (Liver Imaging Reporting and Data System) for all observations in patients with cirrhosis or other conditions placing them at risk for HCC (chronic HBV, advanced fibrosis):
| LI-RADS Category | Interpretation | Action |
|---|---|---|
| LR-1 | Definitely benign | Routine surveillance |
| LR-2 | Probably benign | Routine surveillance |
| LR-3 | Intermediate probability of malignancy | Short-interval follow-up MRI; hepatology discussion |
| LR-4 | Probably HCC | Hepatology/transplant referral |
| LR-5 | Definitely HCC | Hepatology/transplant referral |
| LR-M | Probably or definitely malignant, not HCC-specific | Biopsy consideration; oncology referral |
Common Benign Diagnoses
Simple hepatic cyst: Water attenuation (0–20 HU on CT), imperceptible wall, no internal structure, no enhancement. Can be very large and still require no follow-up if imaging characteristics are typical.
Hemangioma: Most common benign solid liver lesion. Classic CT: hypodense on pre-contrast, peripheral nodular enhancement on arterial phase, progressive fill-in to become isodense on delayed phase. MRI: T2 very bright (lightbulb sign), same enhancement pattern.
FNH: Central scar with spoke-wheel vascularity on arterial phase. T1 isointense, T2 mildly hyperintense, early uniform arterial enhancement, rapid washout. Best confirmed with hepatobiliary-phase MRI (Eovist/gadoxetate): FNH retains contrast on hepatobiliary phase due to functioning bile ducts.
Why This Matters
Hepatic cysts are present in up to 18% of the population and are uniformly benign — the main risk is over-calling them as something requiring follow-up. The key branch point is recognizing cirrhosis, which changes the entire management framework: any observation in a cirrhotic liver is a potential HCC until proven otherwise and should be characterized with LI-RADS rather than the incidental findings algorithm.
Reference
Gore RM, Pickhardt PJ, Mortele KJ, et al. Management of Incidental Liver Lesions on CT: A White Paper of the ACR Incidental Findings Committee. J Am Coll Radiol. 2017;14(11):1429–1437.