Introduction: Hepatitis C infection is highly prevalent worldwide and has a well-known association with B-cell lymphoid malignancies. Antiviral therapy has successfully decreased the rate of liver cirrhosis and improved the outcome in patients with hepatitis C-associated lymphomas. However, although there are a few case reports of aggressive lymphomas after successful hepatitis C therapy, the mechanism behind this association remains unclear. Case Presentation: We present the case of a 55-year-old man with chronic hepatitis C infection and liver cirrhosis who received antiviral therapy with sofosbuvir and ribavirin and achieved a sustained complete virological response. One year after successful therapy, there was an unexplained decline of his liver function and atypical liver nodularity, which led to the diagnosis of a primary liver diffuse large B-cell lymphoma. Discussion: We review the evidence supporting possible mechanisms of lymphomagenesis after successful hepatitis C therapy, particularly involving late “second-hit” mutations after viral-induced DNA damage and antiviral therapy facilitating the emergence of latent malignant B-cell clones by decreasing local inflammation and immune surveillance. More reports may help elucidate any association between hepatitis C antiviral therapy and late lymphoid malignancies.