To which specialist should a patient with hypoattenuating liver lesions with peripheral nodular enhancement be referred?

Referral for Hypoattenuating Liver Lesions with Peripheral Nodular Enhancement

Patients with hypoattenuating liver lesions showing peripheral nodular enhancement should be urgently referred to a hepatobiliary specialist or multidisciplinary hepatobiliary unit, as this imaging pattern has a high positive predictive value (98%) for malignancy. 1

Rationale for Specialist Referral

Imaging Characteristics and Malignancy Risk

• Peripheral nodular enhancement is a concerning radiological feature that strongly suggests metastatic disease
• This enhancement pattern reflects compact tumor cells located in the periphery of most metastases 1
• The majority (72%) of hypoenhancing metastases show peripheral ring enhancement on arterial phase imaging 1

Appropriate Specialist Selection Algorithm:

1. Hepatobiliary Surgical Team/Unit

   • First-line referral for all patients with these lesions
   • Guidelines recommend that "decisions regarding the feasibility of downsizing to resectability should be taken by the regional hepatobiliary unit" 2
   • These specialists are equipped to determine if surgical resection or ablative therapy is appropriate

2. Oncology Referral (after hepatobiliary assessment)

   • For patients with confirmed metastatic disease
   • Particularly important for patients with known primary malignancies (breast, renal cell, thyroid, melanoma, neuroendocrine) 1
   • "Patients with advanced disease unsuitable for liver resection or ablative therapy should be referred to the clinical or medical oncologist" 2

3. Hepatology Referral (concurrent with hepatobiliary assessment)

   • For patients with underlying chronic liver disease or cirrhosis 1
   • Important for evaluation of possible hepatocellular carcinoma (HCC)
   • EASL guidelines recommend that "patients should be discussed in multidisciplinary teams to fully capture and tailor individualised treatment options" 2

Diagnostic Considerations

Differential Diagnosis

• Metastatic disease (most common with this enhancement pattern)
• Hepatocellular carcinoma (particularly in patients with cirrhosis)
• Angiosarcoma metastases (can present with peripheral enhancement in 62% of cases) 3
• Atypical hemangiomas (must be distinguished from true peripheral nodular enhancement) 1

Imaging Recommendations

• Multiphasic imaging including arterial, portal venous, and delayed phases is essential 1
• For lesions >1 cm in cirrhotic patients, diagnosis can be achieved with non-invasive criteria and/or biopsy 2
• "Diagnosis of HCC in patients should be confirmed by pathology" when the enhancement pattern is atypical 2

Common Pitfalls to Avoid

• Confusing peripheral nodular enhancement of metastases with the progressive centripetal filling of hemangiomas 1
• Mistaking perilesional enhancement for true peripheral ring enhancement 1
• Using only portal venous phase imaging may miss up to 14% of metastases 1
• Insufficient diagnostic workup before referral may delay appropriate treatment

Follow-up Recommendations

• For indeterminate lesions <1 cm, follow-up at ≤4-month intervals in the first year 2
• "Repeated bioptic sampling is recommended in cases of inconclusive histological or discordant findings" 2
• Hypoattenuating nodular lesions in chronic liver disease have high malignant potential and require close monitoring 4

The hepatobiliary unit should be the primary referral destination as they are best equipped to coordinate the multidisciplinary approach these complex lesions require, including potential surgical intervention, ablative therapy, or referral to medical oncology when appropriate.