A 52-year-old man with a 20-year history of cirrhosis due to hepatitis B presents with a 3-month history of progressive abdominal distension and weight loss. On examination, he has hepatomegaly and ascites. His AFP level is 450 ng/mL (normal <20 ng/mL). Which investigation is most appropriate to confirm the suspected diagnosis of hepatocellular carcinoma?

Explanation

## Investigation of Choice for HCC Diagnosis ### Clinical Context This patient has cirrhosis with markedly elevated AFP (>400 ng/mL) and clinical features suggestive of hepatocellular carcinoma (HCC). While AFP is a useful tumor marker for screening and monitoring, it is **not diagnostic** on its own. ### Why Contrast-Enhanced Imaging (CT/MRI) is the Gold Standard **Key Point:** Contrast-enhanced CT or MRI is the **imaging modality of choice** for diagnosis of HCC in cirrhotic patients with elevated AFP. **High-Yield:** According to AASLD and EASL guidelines, HCC diagnosis in cirrhotic patients can be made by: - Nodule >10 mm: requires 2 imaging modalities showing arterial enhancement + washout, OR 1 imaging modality + AFP >400 ng/mL - Nodule 10–20 mm: requires 2 imaging modalities with characteristic enhancement pattern - Nodule >20 mm: 1 imaging modality with arterial enhancement + washout is sufficient In this case, with AFP 450 ng/mL, a single contrast-enhanced imaging study (CT or MRI) is diagnostic for HCC if a nodule >10 mm shows arterial enhancement and venous/delayed phase washout. ### Imaging Characteristics of HCC | Feature | CT | MRI | | --- | --- | --- | | Arterial enhancement | Excellent sensitivity | Excellent sensitivity | | Washout (venous/delayed) | Highly specific | Highly specific | | Detection of small nodules | Good | Excellent | | Extrahepatic staging | Excellent | Limited | | Contraindications | Renal impairment (contrast) | Metallic implants, claustrophobia | **Clinical Pearl:** In a cirrhotic patient with AFP >400 ng/mL, a single contrast-enhanced imaging study showing a nodule with arterial phase enhancement and washout is sufficient for HCC diagnosis — **biopsy is not required**. ### Role of Other Investigations **AFP Serial Measurement:** While useful for surveillance and prognostic assessment, serial AFP alone cannot confirm HCC diagnosis. A rising AFP in a cirrhotic patient warrants imaging confirmation. **DCP (Des-gamma-carboxyprothrombin):** An alternative tumor marker with similar sensitivity to AFP but not more specific; used for prognostic assessment and monitoring, not diagnosis. **Liver Biopsy:** Invasive, carries risk of bleeding and tumor seeding; reserved only for atypical imaging findings or non-cirrhotic patients where diagnosis is uncertain. [cite:Harrison 21e Ch 297]