Karsinoma Hepatoselular (HCC)

01Pathophysiology

Hepatocellular carcinoma arises from malignant transformation of hepatocytes through a well-characterized sequence of chronic injury, regeneration, fibrosis, cirrhosis, dysplastic nodule formation, and ultimately carcinoma. The constant cycle of hepatocyte death and proliferation creates an environment of genomic instability, where oncogenic mutations accumulate over years to decades.

Hepatitis B deserves special attention because it is a DNA virus that integrates directly into the host hepatocyte genome. This insertional mutagenesis can activate proto-oncogenes or disrupt tumor suppressor genes, which is why HBV can cause HCC even in the absence of cirrhosis. This is a frequently tested distinction: HBV does not require cirrhosis as an intermediate step, whereas hepatitis C (an RNA virus that does not integrate into the genome) drives carcinogenesis almost exclusively through the chronic inflammation-cirrhosis pathway.

Aflatoxin B1, produced by Aspergillus species that contaminate poorly stored grains and peanuts (particularly in sub-Saharan Africa and Southeast Asia), causes a characteristic G-to-T transversion mutation at codon 249 of the TP53 tumor suppressor gene (the R249S hotspot mutation). When aflatoxin exposure combines with chronic HBV infection, the risk of HCC is synergistically amplified.

A critical concept for understanding HCC imaging is the arterialization of blood supply. Normal hepatic parenchyma receives roughly 75% of its blood from the portal vein and 25% from the hepatic artery. As hepatocytes progress from regenerative nodule to dysplastic nodule to frank HCC, they progressively lose portal venous inflow and develop neoangiogenesis from the hepatic artery. This shift to predominantly arterial feeding is the pathophysiological basis for the hallmark imaging pattern: bright arterial phase enhancement followed by washout in the portal venous and delayed phases.

HCC also has a tendency toward vascular invasion, particularly into the portal vein (portal vein tumor thrombus) and hepatic veins. Invasion of the hepatic veins or inferior vena cava can produce Budd-Chiari syndrome as a presenting feature, with rapid-onset ascites, hepatomegaly, and abdominal pain.

Paraneoplastic syndromes occur because HCC cells can produce ectopic hormones: erythropoietin (causing erythrocytosis/polycythemia), PTH-related peptide (causing hypercalcemia), and insulin-like growth factor-2 (causing refractory hypoglycemia). Recognizing these paraneoplastic presentations in a patient with known liver disease should raise suspicion for HCC.

02Classification and Clinical Manifestation

Barcelona Clinic Liver Cancer (BCLC) Staging

Child-Pugh Classification (Referenced for Staging)

Child-Pugh A = 5-6 points, B = 7-9 points, C = 10-15 points.

Paraneoplastic Manifestations

03Diagnostic Workup

Surveillance strategy. All patients with cirrhosis (regardless of cause) and patients with chronic hepatitis B (even without cirrhosis) should undergo ultrasound every 6 months with or without serum AFP. This is the best initial screening test. The rationale for including non-cirrhotic HBV carriers is the ability of HBV to cause HCC through direct DNA integration, bypassing the cirrhosis requirement.

When a nodule is found on surveillance ultrasound, the next step depends on its size. For lesions < 1 cm, the recommendation is to repeat ultrasound in 3 to 4 months because most sub-centimeter nodules are regenerative rather than malignant. For lesions ≥ 1 cm, the patient should proceed to multiphasic contrast-enhanced CT or MRI.

The diagnostic imaging pattern is one of the most testable concepts in HCC. Because HCC receives its blood supply from the hepatic artery (arterialization), the tumor enhances brightly during the arterial phase of contrast injection. Then, during the portal venous and delayed phases, the contrast washes out of the tumor faster than it washes out of the surrounding liver parenchyma, making the tumor appear darker relative to background liver. This combination of arterial hyperenhancement followed by washout is considered diagnostic and in most cases eliminates the need for biopsy.

Biopsy is generally NOT needed when a lesion ≥ 1 cm in a cirrhotic liver demonstrates the classic arterial enhancement and washout pattern. This is an important testing point: ordering a biopsy when imaging is characteristic is not only unnecessary but carries risk of tumor seeding along the needle tract and hemorrhage in patients who are often coagulopathic from liver disease. Biopsy is reserved for lesions with indeterminate imaging features that do not show the classic pattern.

AFP as a standalone test has limited sensitivity (approximately 60%) and limited positive predictive value, particularly at low elevations. AFP can be elevated in chronic hepatitis, pregnancy, and nonseminomatous germ cell tumors. An AFP level >400 ng/mL in a patient with a liver mass and known risk factors is highly suggestive, but a normal AFP should never be used to rule out HCC.

04Management and Treatment

Curative intent therapies. Only BCLC stage 0 and A patients are candidates for potentially curative treatment. Surgical resection is the first-line curative option for patients with a single tumor, no portal hypertension (hepatic venous pressure gradient < 10 mmHg), and well-preserved synthetic function (Child-Pugh A, normal bilirubin). Resection is preferred over transplant when liver function can tolerate it because it avoids the waitlist and immunosuppression.

Liver transplantation is the ideal treatment when the patient has HCC within the Milan criteria (single tumor ≤ 5 cm, or 2-3 tumors each ≤ 3 cm, with no vascular invasion and no extrahepatic disease) AND has underlying liver disease that would make resection unsafe (e.g., Child-Pugh B or C, significant portal hypertension). Transplantation treats both the cancer and the underlying cirrhosis simultaneously, which is its greatest advantage. Patients awaiting transplant often receive bridging therapy (ablation or TACE) to prevent tumor progression beyond Milan criteria while on the waitlist.

Local ablation with radiofrequency ablation (RFA) or microwave ablation is recommended for patients with very early or early stage tumors (ideally < 3 cm) who are not candidates for resection or transplantation. For tumors smaller than 2 cm, ablation achieves complete necrosis rates exceeding 90% and outcomes comparable to resection.

TACE is the standard of care for intermediate-stage (BCLC B) patients with multinodular tumors confined to the liver, without vascular invasion. TACE works by delivering chemotherapy (typically doxorubicin or cisplatin) directly into the hepatic artery branches feeding the tumor, followed by embolization to cut off the arterial blood supply. The rationale relies on the arterialized blood supply of HCC: normal hepatocytes survive because they are fed by the portal vein, while tumor cells that depend on arterial flow undergo ischemic necrosis.

Systemic therapy is indicated for advanced-stage HCC with portal vein invasion, extrahepatic spread, or progression after locoregional therapy. The current first-line regimen is atezolizumab (anti-PD-L1, 1200 mg IV every 3 weeks) plus bevacizumab (anti-VEGF, 15 mg/kg IV every 3 weeks). Before starting bevacizumab, patients must undergo upper endoscopy to screen for and treat esophageal varices, because bevacizumab carries a risk of life-threatening GI hemorrhage. In patients who cannot receive immunotherapy (active autoimmune conditions, prior solid organ transplant recipients on immunosuppression), sorafenib 400 mg orally twice daily or lenvatinib (dosed by body weight: 12 mg daily if ≥ 60 kg, 8 mg daily if < 60 kg) are alternatives.

Contraindications and cautions. Bevacizumab is contraindicated in patients with untreated or high-risk varices, recent GI bleeding, or poorly controlled hypertension. Sorafenib requires monitoring for hand-foot skin reaction, diarrhea, and hypertension. Neither systemic regimen is appropriate in patients with Child-Pugh C liver function, who should receive supportive care only.

05Differential Diagnosis and Distractors

06Traps and High-Yield Pearls

The single most tested concept in HCC is the imaging pattern. You must be able to recognize that arterial phase hyperenhancement followed by portal venous/delayed phase washout in a cirrhotic liver is diagnostic and does not require biopsy confirmation. A common trap is a question stem that presents a classic imaging pattern and then offers "biopsy" as an answer choice. Selecting biopsy in this scenario is wrong and reflects a misunderstanding of the diagnostic algorithm: biopsy is reserved only for lesions with indeterminate imaging.

A second frequent trap involves AFP interpretation. Students often incorrectly believe that a normal AFP rules out HCC. Because AFP sensitivity is only around 60%, a normal value in a patient with a suspicious liver lesion and risk factors should never delay further imaging workup. Conversely, a mildly elevated AFP (< 200 ng/mL) can be seen in active hepatitis or cirrhosis without cancer, so do not jump to a diagnosis of HCC based on AFP alone.

The hepatitis B exception is heavily tested. Most questions will present HCC in the setting of cirrhosis, but occasionally a vignette will describe a non-cirrhotic patient with chronic HBV who presents with a liver mass. Students who have internalized "HCC requires cirrhosis" will be tripped up. Remember that HBV causes HCC through direct genomic integration, which is independent of the cirrhosis pathway.

Milan criteria appear frequently in questions about transplant eligibility. The numbers to memorize are: single lesion ≤ 5 cm, or up to 3 lesions each ≤ 3 cm, with no macrovascular invasion and no extrahepatic spread. A common distractor is a patient who meets size criteria but has portal vein tumor thrombus on imaging, which disqualifies them from transplant.

Finally, watch for questions about systemic therapy sequencing. The current first-line standard is atezolizumab plus bevacizumab, but the vignette may describe a post-transplant patient (on immunosuppression) or a patient with autoimmune hepatitis. In these cases, immunotherapy is contraindicated, and the correct answer is sorafenib or lenvatinib. The core competency being tested is your ability to match the right treatment to the right patient based on tumor stage, liver reserve, and contraindications to standard regimens.