Laparoscopic excision of a giant retroperitoneal benign mesenteric cyst encasing the left ureter and iliac vessels: a rare case report and literature review

Abstract

Retroperitoneal mesenteric cysts are exceedingly rare benign intra-abdominal tumors that pose significant diagnostic and therapeutic challenges due to their silent progression, large potential size, and proximity to major retroperitoneal neurovascular and urinary structures. We present the case of a 59-year-old postmenopausal female presenting with chronic, intermittent left-sided abdominal pain for three years and progressive urinary hesitancy for one year. Advanced imaging delineated a giant, thin-walled, unilocular retroperitoneal cystic lesion measuring approximately 12.6 × 11.4 × 10.9 cm, causing severe extrinsic compression, displacement, and complete encasement of the left ureter and left common iliac artery, resulting in moderate hydronephrosis. Despite the immense size and complex anatomic adherence, the patient successfully underwent a minimally invasive Laparoscopic Excision of the giant cyst with meticulous dissection and preservation of the encased ureter and iliac vessels. Following complete isolation, controlled aspiration was safely executed without spillage to downsize the specimen for extraction, avoiding open conversion. Histopathological evaluation confirmed a benign mesenteric cyst of retroperitoneal origin. The patient experienced an uneventful postoperative recovery with immediate resolution of urinary and painful symptoms. This case underscores that with advanced laparoscopic expertise and precise anatomical navigation, giant adherent retroperitoneal cysts can be safely managed via minimally invasive pathways, avoiding the morbidity of open conversion.