A 65-year-old patient has been suffering from liver cirrhosis associated with hepatitis C virus for 7 years. During the last 3 weeks the patient developed severe edema of the lower extremities, the abdomen is significantly distended with fluid. Ultrasound: signs of liver cirrhosis, portal hypertension, lymph nodes are in the area of hepatic portal. Concentration of α-fetoprotein in blood serum is 285 ng/ml. What complication could have developed in this case?