Laparoscopic resection of a primary retroperitoneal mucinous cystadenoma: a case report.

Introduction: Primary retroperitoneal mucinous cystadenoma (PRMC) is a rare tumor of uncertain origin, predominantly affecting women. Most cases are asymptomatic or present with nonspecific symptoms, making diagnosis challenging due to its retroperitoneal location and lack of distinct clinical signs. Case presentation: A 47-year-old woman presented with progressive abdominal distension, altered bowel habits, and flatulence. A 12-cm palpable mass was detected in the right flank. Abdominal computed tomography demonstrated a well-defined cystic lesion adjacent to the ascending colon. The patient was evaluated and treated at a tertiary care academic hospital. Elective laparoscopic excision was performed using indocyanine green for real-time intraoperative ureteral visualization. The procedure was completed without complications. Histopathological analysis confirmed PRMC, with mucinous epithelium lacking atypia and no evidence of malignancy. Discussion: Although PRMC shares features with ovarian mucinous tumors, it arises independently in the retroperitoneum and is often difficult to diagnose preoperatively due to the absence of specific clinical or radiological signs. Imaging studies can help delineate the lesion, but definitive diagnosis depends on histopathological confirmation. Complete surgical excision without rupture is essential to avoid recurrence or potential malignant transformation. Minimally invasive resection, when feasible, offers a safe and effective therapeutic option with low morbidity. Conclusion: PRMC should be considered in the differential diagnosis of retroperitoneal cystic lesions in women. Laparoscopic excision was safe and effective in this case. A long-term follow-up is recommended due to the risk of recurrence.