Extremely high titer of hepatitis B surface antigen antibodies in a primary hepatocellular carcinoma patient: A case report

BACKGROUND: Hepatocellular carcinoma (HCC) may be caused by hepatitis B virus (HBV) infection. Post-infection recovery-associated changes of HBV indicators include decreased hepatitis B surface antigen (HBsAg) level and increased anti-HBsAg antibody titer. Testing to detect HBV DNA is conducted rarely but could detect latent HBV infection persisting after acute infection and prompt administration of treatments to clear HBV and prevent subsequent HBV-induced HCC development. Here, we present an HCC case with an extremely high anti-HBsAg antibody titer and latent HBV infection. CASE SUMMARY: A 57-year-old male patient with abdominal pain who was diagnosed with primary HCC presented with an extremely high level (over 2000 ng/mL) of serum alpha-fetoprotein. Abdominal B-ultrasonography and computed tomography scan results indicated focal liver lesion and mild splenomegaly. Assessments of serological markers revealed a high titer of antibodies against hepatitis B core antigen (anti-HBcAg antibodies), an extremely high titer (1000 mIU/mL) of hepatitis B surface antibodies (anti-HBsAg antibodies, anti-HBs) and absence of detectible HBsAg. Medical records indicated that the patient had reported no history of HBV vaccination, infection or hepatitis. Therefore, to rule out latent HBV infection in this patient, a serum sample was collected then tested to detect HBV DNA, yielding a positive result. Based on the aforementioned information, the final diagnosis was HCC associated with hepatitis B in a compensated stage of liver dysfunction and the patient was hospitalized for surgical treatment. CONCLUSION: A rare HCC case with high serum anti-HBsAg antibody titer and detectable HBV DNA resulted from untreated latent HBV infection.