Abstract
BACKGROUND: Endometrioid adenocarcinoma is usually diagnosed by endometrial curettage with a positive rate of 94%, while a hysteroscopic examination can increase the positive rate. Differently, endometrioid adenocarcinoma arising from adenomyosis (EAAFA) is always misdiagnosed, even after endometrial curettage or hysteroscopy. EAAFA is rarely reported. CASE DESCRIPTION: We reported two cases of EAAFA with long-term follow-ups of 9-10 years. The two cases were misdiagnosed even if endometrial curettage or hysteroscopy was performed. One case complained of postmenopausal vaginal bleeding with elevated CA199, and she was diagnosed by fast-frozen pathology during hysterectomy, followed by bilateral salpingo-oophorectomy and pelvic lymphadenectomy. In another case, a premenopausal woman with acquired progressive dysmenorrhea was diagnosed as EAAFA by the histopathological result after a transvaginal hysterectomy and had to undergo reoperation. The FIGO stage was IB in both cases. Chemotherapy or radiotherapy was performed after the operation. Patients were followed up for 9-10 years, with no metastasis or recurrence being observed. CONCLUSION: The diagnosis of EAAFA is always delayed because of tumor-free eutopic endometrium and negative results of the endometrial curettage or hysteroscopy examination. Fast-frozen pathology of the whole uterus helps diagnose EAAFA precisely and avoids reoperation. Adenocarcinoma foci of EAAFA usually involve the myometrium deeply. A better prognosis of EAAFA should be expected due to good differentiation and negative lymphovascular space invasion.