What is the diagnosis for a patient with intermittent low-grade fever, malaise, weight loss over one month, and a 6cm liver mass on ultrasound (US), considering options such as hepatocellular carcinoma (HCC), hydatid cyst, or hemangioma?

Diagnosis: Hepatocellular Carcinoma (HCC)

The most likely diagnosis is hepatocellular carcinoma (HCC), given the constellation of constitutional symptoms (fever, malaise, weight loss) over one month combined with a 6cm liver mass. 1

Clinical Reasoning

Why HCC is Most Likely

• Constitutional symptoms strongly favor malignancy: The triad of intermittent low-grade fever, malaise, and weight loss over one month points toward a malignant process rather than benign pathology 1

• Size matters critically: At 6cm, this mass exceeds the threshold where HCC becomes highly probable, particularly when symptomatic 1

• HCC commonly presents with systemic symptoms: Unlike hemangiomas which are typically asymptomatic, HCC frequently causes constitutional symptoms including fever, weight loss, and malaise as part of paraneoplastic phenomena 1

Why NOT Hemangioma

• Hemangiomas are asymptomatic in >95% of cases: These benign vascular lesions rarely cause constitutional symptoms unless they are massive (>10cm) or undergo thrombosis 2

• No fever or weight loss with hemangiomas: The presence of fever, malaise, and weight loss over one month makes hemangioma extremely unlikely 2

Why NOT Hydatid Cyst

• Hydatid cysts typically present differently: While hydatid disease can cause fever, it usually presents with right upper quadrant pain, hepatomegaly, or allergic symptoms rather than the insidious constitutional symptoms described 3, 4

• Weight loss and malaise are uncommon with uncomplicated hydatid: These symptoms suggest either complicated hydatid disease (rupture, secondary infection) or an alternative diagnosis 3, 5

• Geographic and exposure history is critical: Hydatid disease requires exposure to endemic areas and contact with dogs/livestock, which should be specifically elicited 3, 4

Diagnostic Algorithm

Immediate Next Steps

1. Check alpha-fetoprotein (AFP): If AFP >200 ng/mL with typical imaging features, diagnosis of HCC can be made without biopsy 1

2. Obtain dynamic contrast-enhanced imaging: Either multiphase CT or MRI to look for arterial hypervascularity with venous/delayed phase washout—the hallmark of HCC 1

3. Assess for chronic liver disease: Check hepatitis B surface antigen, hepatitis C antibody, liver function tests (albumin, bilirubin, PT/INR), and platelet count 1

Imaging Characteristics to Confirm HCC

• Arterial phase hypervascularity with washout in portal venous or delayed phases is diagnostic for HCC in cirrhotic patients 1

• For a 6cm mass with these features and AFP >200 ng/mL, biopsy is unnecessary 1

Critical Pitfall to Avoid

Do not assume benign pathology based on ultrasound alone: A 6cm mass with constitutional symptoms requires definitive characterization with contrast-enhanced CT or MRI, regardless of initial ultrasound appearance 1

Risk Factors to Elicit

• Hepatitis B or C infection: Most important risk factors globally 1
• Alcohol use: Alcoholic cirrhosis is a major HCC risk 1
• Metabolic syndrome/obesity: Non-alcoholic fatty liver disease is an emerging cause 1
• Geographic exposure: For hydatid consideration, ask about pastoral area residence and dog contact 3, 4

Rare but Documented Scenario

While extremely uncommon, synchronous HCC and hydatid cyst can coexist in the same liver, particularly in patients with hepatitis B and endemic exposure 3, 4, 5, 6. However, the constitutional symptoms still point toward the malignant component as the primary concern requiring urgent evaluation.