Appendiceal Endometriosis Mimicking Ovarian Torsion: A Rare Intraoperative Finding

Endometriosis remains a leading cause of pelvic pain and infertility among reproductive-aged women, typically involving the ovaries, uterosacral ligaments, or pelvic peritoneum. However, gastrointestinal manifestations, particularly appendiceal endometriosis, are exceedingly rare and frequently asymptomatic, making diagnosis challenging. When symptomatic, appendiceal involvement may mimic acute surgical conditions such as appendicitis or adnexal torsion, complicating clinical evaluation. We report a case of a 35-year-old woman with a seven-year history of secondary infertility who presented with acute right lower abdominal pain. Initial sonographic evaluation revealed a complex, avascular right adnexal mass, raising concerns for ovarian torsion. Laparotomy was performed, revealing a dark cystic lesion near the right adnexa, extensive pelvic adhesions, and an inflamed appendix. Histopathological analysis of the resected appendix confirmed endometriosis, characterized by the presence of endometrial glands and stroma within the muscularis propria. The patient recovered uneventfully and was referred for infertility management. This case underscores the diagnostic ambiguity posed by appendiceal endometriosis and highlights the importance of intraoperative assessment and histologic confirmation. In women of reproductive age presenting with nonspecific right lower quadrant pain and adnexal pathology, appendiceal endometriosis should be considered in the differential diagnosis. Early recognition may prevent unnecessary adnexal intervention and inform future fertility care. Routine evaluation of the appendix during gynecologic surgery may offer valuable diagnostic insights in atypical presentations.