Mesenchymal Hamartoma of the Liver in Two Older Children and a Review of Pediatric Cases in Japan

Abstract

Introduction: Mesenchymal hamartoma of the liver (MHL) is a rare pediatric benign hepatic tumor that affects infants under the age of three years. MHL is also considered to be the origin of undifferentiated embryonal sarcoma, a malignant liver tumor. To improve outcomes and understand its pathophysiology, it is important to analyze the clinical characteristics of MHL. We report on two cases of MHL in older children and review the clinical characteristics of 81 cases in Japan, including our two cases. Case 1: The patient was a five-year-old girl. A 15 cm multicystic mass was found in the left lobe. The AFP level was normal. The patient underwent a left lobectomy. A tumor diagnosis of MHL was concluded. No recurrence has been detected in the 3.8 years after surgery. Case 2: The patient was a 15-year-old girl. An 8 cm multicystic mass was found in the S7/8 right lobes with tooth-like calcifications in the cyst wall. The preoperative diagnosis was hepatic teratoma. The patient underwent an extended right posterior hepatic segmentectomy. A tumor diagnosis of MHL was concluded. Conclusions: In our cases, no recurrence has been detected in over three years after surgery. However, in the review of 81 cases in Japan, recurrence was observed in three cases, one of which was suspected to be malignant transformation. According to the biological characteristics of MHL, complete resection of the tumor is essential.