Diagnosis of endometrioid adenocarcinoma of the fallopian tube misinterpreted as ovarian cancer: a case report

Primary fallopian tube cancer is a rare gynecologic malignancy, often misdiagnosed as ovarian cancer due to overlapping clinical and radiologic features. We report a case of a 49-year-old woman presenting with abnormal uterine bleeding and lower abdominal pain. Imaging revealed bilateral adnexal masses and elevated CA 125, HE4, and ROMA index. Surgical exploration identified a left fallopian tube tumor and omental involvement. Histopathology confirmed high-grade endometrioid adenocarcinoma of the left fallopian tube with metastatic deposits. The patient underwent total hysterectomy, bilateral salpingo-oophorectomy, omentectomy, and adjuvant chemotherapy with Paclitaxel and Carboplatin. This case underscores the diagnostic challenge and clinical significance of recognizing fallopian tube carcinoma in patients with adnexal masses and elevated tumor markers.