Very early stage adenocarcinoma arising from adenomyosis in the uterus

Objective: Malignant transformations of adenomyosis in premenopausal women with normal endometrium are extremely rare. We report a case of adenocarcinoma arising from an adenomyotic focus in the uterus, which was found unexpectedly in a woman undergoing myomectomy for adenomyosis. Case Report: A 47-year-old premenopausal woman presented with massive vaginal bleeding and anemia. She was admitted and underwent myomectomy under the initial diagnosis of uterine leiomyoma. Microscopic studies revealed endometrioid adenocarcinoma, which was a malignant transformation of a focus of adenomyosis in the surgical specimen. A total hysterectomy and bilateral salpingo-oophorectomy with pelvic and para-aortic lymphadenectomy was then performed. Pathologic studies showed no residual tumors in the entire resected specimen except for the previous lesion. The endometrium had normal thickness with mild proliferative activity throughout the cavity. There was no atrophic or hyperplastic change in the whole endometrium. The adenocarcinoma was present exclusively in the myometrium, and a transition between the carcinoma and the adenomyotic glands was observed. Conclusion: This case report presents evidence that adenocarcinoma may arise de novo from an adenomyotic lesion in the uterus.