Abstract
RATIONALE: The spontaneous hepatocellular carcinoma (HCC) regression is rare. The underlying mechanism remains unclear. Elucidating this mechanism may lead to a novel HCC treatment, especially in the era of immunotherapy, because immunological reactions are among the possible mechanisms of spontaneous HCC regression. PATIENT CONCERNS: A 63-year-old man fell and fractured his right olecranon. Before surgery for bone fracture, an abnormal liver function test result was noted and HCC was also suspected by ultrasonography and tumor markers. The patient was a heavy drinker and a daily smoker and was instructed to abstain from alcohol and smoking. DIAGNOSES: HCC was definitively diagnosed by dynamic computed tomography immediately after surgery for bone fracture. The main tumor was 6 cm in size and was accompanied by multiple small lesions. INTERVENTIONS: Immediately before starting treatment for HCC, tumor markers were markedly decreased (alpha-fetoprotein, from 3098 to 361 ng/mL; des-gamma-carboxy prothrombin, from 2083 to 47 mAU/mL). Considering the possibility of spontaneous regression of the tumors, the patient was followed carefully without treatment. OUTCOMES: During the follow-up without treatment, the tumor markers decreased further, and the tumors disappeared from the image. LESSONS: Alcohol and smoking abstinence and surgical procedures were considered possible causes for the spontaneous HCC regression.