Cecal leiomyoma mimicking a right adnexal mass: A rare diagnostic challenge

Adnexal masses in reproductive-age women can pose diagnostic challenges due to overlapping imaging findings. We present the case of a 34-year-old woman with chronic lower abdominal pain and a right adnexal mass on imaging, initially interpreted as an ovarian fibroma or uterine myoma. Pelvic examination revealed no uterine or adnexal abnormalities. Intraoperative exploration identified an 8 cm firm mass arising from the cecal wall. Colonoscopy confirmed external compression of the cecum without mucosal involvement. The lesion was excised via right hemicolectomy, and histopathology with immunohistochemistry confirmed a benign cecal leiomyoma. The tumor showed diffuse H-caldesmon positivity and was negative for CD117, DOG1, CD34, and S100. This case highlights the diagnostic limitations of imaging alone and emphasizes the importance of pelvic examination and multidisciplinary collaboration in evaluating adnexal masses. Considering rare gastrointestinal tumors in the differential diagnosis may help prevent unnecessary gynecologic procedures and improve clinical outcomes. This case underscores the need to consider nongynecologic origins in adnexal mass evaluation.