Laparoscopic resection of a low-grade appendiceal mucinous neoplasm in a patient with autosomal dominant polycystic kidney disease: a case report.

Introduction and importance: Appendiceal mucinous neoplasms (AMNs) are rare, and preoperative diagnosis can be challenging, particularly when other abdominal cystic diseases coexist. Autosomal dominant polycystic kidney disease (ADPKD), which is characterized by multiple cystic formations, can complicate both differential diagnosis and surgical planning. Case presentation: A 77-year-old man with ADPKD and chronic renal failure was referred to our hospital following a positive fecal occult blood test during an evaluation for anemia. Colonoscopy revealed a large submucosal tumor-like elevation in the cecum, obscuring the appendiceal orifice. Non-contrast computed tomography showed multiple abdominal cysts and a low-attenuation lesion protruding into the cecal lumen with tubular extension outside the cecum. An AMN was suspected, although the potential for malignancy and pseudomyxoma peritonei could not be completely excluded. Despite concerns that the cysts might limit the operative view, pneumoperitoneum provided adequate visualization since the cysts were primarily retroperitoneal. Laparoscopic ileocecal resection with D2 lymph node dissection and primary ileocolic anastomosis was completed without tumor rupture. No ileostomy was created. The postoperative course was uneventful. Histopathological examination confirmed a low-grade AMN. No recurrence was observed 9 months postoperatively. Clinical discussion: This case underscores the challenge of differentiating AMNs from other cystic lesions in patients with ADPKD and suggests that cyst distribution may influence the surgical approach and exposure. Conclusion: Laparoscopic surgery may be a feasible option for patients with multiple abdominal cystic diseases when the cysts are predominantly located in the retroperitoneum.