-Case Report-

Laparoscopic Resection of a Large Mucinous Cystic Neoplasm of the Liver: A Case Report

Yuto Aoki¹, Yukio Oshiro¹, Ryo Ga¹, Mampei Kawashima¹, Chikako Hasegawa², Youichi Kawano³, Junji Ueda³, Yoshiharu Nakamura¹ and Hiroshi Yoshida³

¹Department of Gastroenterological Surgery, Nippon Medical School Chiba Hokusoh Hospital, Chiba, Japan
²Department of Pathology, Nippon Medical School Chiba Hokusoh Hospital, Chiba, Japan
³Department of Gastroenterological Surgery, Nippon Medical School, Tokyo, Japan

Mucinous cystic neoplasms of the liver (MCNs-L) are rare cystic tumors characterized by multilocular cysts lined with a mucin-producing epithelium and supported by ovarian-like stroma. These tumors account for <5% of all cystic liver lesions and carry a potential risk of malignant transformation, necessitating early diagnosis and surgical resection. This report describes the successful laparoscopic partial liver resection of segments 4 and 5 for a large MCN-L in a woman in her 40s who presented with upper abdominal discomfort. Imaging studies revealed a multilocular cystic lesion measuring 11.9 × 8.5 × 13.0 cm in segments 4 and 5 of the liver. The primary challenges were the size of the lesion and the need to prevent cystic content spillage during surgery. Using meticulous techniques, including the use of a retrieval bag and controlled aspiration, we successfully excised the tumor laparoscopically and without contamination. Pathological analysis confirmed a diagnosis of mucinous cystic adenoma with no evidence of malignancy. The patient recovered uneventfully and was discharged on postoperative day 7. This case highlights the feasibility and safety of a laparoscopic approach for large MCNs-L. Furthermore, it underscores the importance of preoperative planning, precise surgical techniques, and measures to prevent cystic content dissemination. Minimally invasive surgery offers significant benefits, including reduced recovery time and improved cosmetic outcomes, and can be effectively applied to large hepatic cystic lesions by experienced surgical teams.

J Nippon Med Sch 2026; 93: 415-421

Keywords
mucinous cystic neoplasm of the liver, laparoscopic liver resection, minimally invasive surgical procedures, hepatic cysts, surgical techniques

Correspondence to
Yuto Aoki
yutoaoki@nms.ac.jp

Received, March 6, 2025
Accepted, April 23, 2025