Mesenchymal hamartomas of the liver are benign tumors with confusing etiology, mostly observed in children not more than two years of age, but hardly ever in adults. Here we present a case of a 25-year-old patient with postinfectious cirrhosis of the liver and portal hypertension, after numerous surgical interventions in the abdominal cavity, whose radiographic examinations revealed a hypervascularized pathological mass in the direct vicinity of the stomach, suspected to be a gastrointestinal stromal tumor. In view of a high risk of complication in the perioperative period (based on the MELD score the risk of death due to cirrhosis of the liver was estimated as 10%), the qualification for the operation was preceded by detailed diagnostics, which did not confirm an expansive disease. After diagnostic possibilities had run out the patient was qualified for surgery, in which a well-isolated solid tumor, 4 cm in diameter, was removed from the hepatoduodenal ligament area. A microscopic examination of the tumor revealed the presence of mesenchymal stroma, hepatocytes and bile duct epithelium. The histopathological image was interpreted as ectopic mesenchymal hamartoma of the liver.