A 48-year-old woman from Mumbai with a 5-year history of cirrhosis (HCV-positive) undergoes routine surveillance ultrasound. A 2.5 cm nodule is detected in the right lobe of the liver. Serum alpha-fetoprotein (AFP) is 180 ng/mL (normal <20 ng/mL), and hepatitis C RNA is detectable. CT abdomen with contrast shows arterial phase enhancement of the nodule. Which of the following best describes the diagnostic significance of the elevated AFP in this clinical scenario?

Explanation

## AFP in Hepatocellular Carcinoma **Key Point:** AFP is a glycoprotein normally produced by fetal liver and yolk sac. In HCC, elevated AFP (>20 ng/mL) is present in ~60–70% of cases and correlates with tumor burden and prognosis. However, AFP elevation ALONE is not diagnostic. ## Diagnostic Criteria for HCC in Cirrhosis (AASLD/EASL) | Nodule Size | Diagnostic Criteria | |--------------|--------------------| | **>20 mm** | One imaging modality (CT/MRI) with arterial enhancement + washout, OR AFP >400 ng/mL | | **10–20 mm** | Two imaging modalities with arterial enhancement + washout, OR one imaging modality + AFP >400 ng/mL | | **<10 mm** | Surveillance; repeat imaging in 3–4 months | **Clinical Pearl:** In this case, the nodule (2.5 cm) shows arterial enhancement on CT, which ALONE meets diagnostic criteria for HCC in a cirrhotic patient. The elevated AFP (180 ng/mL) is supportive but does NOT change the diagnosis—imaging findings are primary. **High-Yield:** AFP levels: - **<400 ng/mL:** Supportive but not diagnostic alone - **>400 ng/mL:** Highly suggestive in cirrhosis with imaging findings - **Benign elevations:** Cirrhosis, hepatitis, pregnancy, germ cell tumors **Mnemonic:** AFP is **S**ensitive but not **S**pecific → need imaging confirmation.