Background : Mesenchymal hamartoma is a rare type of benign tumor which usually occurs in the pediatric period characterized by an admixture of epithelial structures in a loose connective tissue stroma with fluid accumulation suggestive of lymphangiomatous channels. Successful resolution in cases of complicated adult mesenchymal hamartoma is hardly seen. Due to their rarity, discussing each clinical experience is necessary.

Methods : We report an unusual case of a cystic mesenchymal hamartoma of liver in an 22-year-old male who presented to the urgent emergency department with dyspnea and abdominal discomfort. Computed tomography and magnetic resonance imaging of the liver showed 25cm size septated cystic mass with three enhancing portion and calcification in the right liver lobe. Additional imaging evaluation confirmed infrarenal Inferior vena cava (IVC) thrombosis and multifocal pulmonary thromboembolism (PTE).

Results : In the process of treating heparin therapy, embolotherapy was performed due to repeated bleeding from a large hemorrhagic cyst, and PTE improvement was confirmed, so IVC filter insertion was performed preoperatively. He underwent modified central bisectionectomy of the liver. Pathological examination revealed a mesenchymal hamartoma. The patient recovered without any postoperative complications and was discharged in good condition on postoperative day 10 with IVC filter removal.

Conclusions : To improve the therapeutic management of complicated adult mesenchymal hamartoma of ther liver. it is necessary to discuss each clinical experience and consider an appropriate method for the preoperative diagnosis and treatment.