Background: Neuroendocrine tumors (NETs) or carcinoid tumors are rare neoplasms originating from neuroendocrine cells, most commonly found in the ap-pendix. While NETs are often asymptomatic, they may present with abdominal pain, flushing, and diarrhea and are frequently discovered incidentally during surgery for other conditions. Endometriosis has been associated with an increased risk of certain malignancies; however, its relationship with NETs remains unclear. Given the high frequency of laparoscopic surgeries for endome-triosis, incidental NET findings pose unique clinical challenges.
Methods: This retrospective case report was conducted at Avicenna Fertility Center, Affiliated to Avicenna Research Institute, Tehran, Iran, from 2016 to 2024. Medical records of six patients (33-55 years old) who underwent laparoscopic surgery for endometriosis, with incidental NETs found in the appendix, were analyzed. Clinical presentation, intraoperative findings, histopathology, and postoperative outcomes were reviewed.
Results: Six women (mean age: 43.7 years) with endometriosis-related symptoms (dysmenorrhea, dyspareunia, and pelvic pain) underwent laparoscopic surgery with appendectomy. The NETs (2–9 mm, all G1, Ki-67 <3%) exhibited invasion into the muscularis propria in three cases and into the subserosal fat in one case; lymph nodes were not evaluated, and no metastases were detected. Immunohistochemistry confirmed neuroendocrine differentiation, with positive chromogranin and synaptophysin staining. Follow-up over 1–5 years showed no evidence of recurrence. 
Conclusion: Incidental NET detection during endometriosis surgery highlights the need for routine pathological examination of appendectomy specimens. While no direct link exists between NETs and endometriosis, recognizing these tumors may influence surgical decisions and postoperative management, emphasizing the importance of multidisciplinary care.