Serous carcinoma arising from uterine adenomyosis/adenomyotic cyst of the cervical stump: a report of 3 cases

BACKGROUND Serous carcinoma arising in adenomyosis and adenomyotic cyst is very rare. Only 3 serous carcinomas and 5 serous endometrial intraepithelial carcinomas (EIC) have been reported to date. METHODS We reviewed the clinicopathological features of 2 serous carcinoma in uterine adenomyosis and 1 serous EIC in adenomyotic cyst of the cervical stump. RESULTS Case 1 had an endometrial serous carcinoma in the uterine myometrium and the left ovary. A minor component of benign endometrial glands with minimal endometrial stroma was found in the uterine mass and the surrounding myometrium. Case 2 showed 3 small foci of serous carcinoma, serous EIC and endometrial glandular dysplasia (EmGD) in the adenomyosis. Scanty serous carcinoma was present in the endometrium without evidence of myometrial invasion. The eutopic endometrium in both case 1 and 2 had no evidence of neoplastic changes after complete examination. Case 3 had 3 microscopic serous EICs in the adenomyotic cysts of the cervical stump. One EIC lesion coexisted with EmGD. No cancer was found in the endocervical tube although the preoperative endocervical biopsy showed a poorly differentiated endometrioid carcinoma. Immunohistochemistry demonstrated that serous carcinoma in case 1 and EIC in all 3 cases showed a characteristic pattern of p53 and p16 over expression, high Ki67 index, and lack of WT1, ER and PR staining. EmGD in case 1 and 3 had a similar staining pattern except a lower Ki67 index and the presence of ER expression. CONCLUSIONS We believe that this case series may expand our recognition on serous carcinoma arising in uterine adenomyosis/adenomyotic cyst including extra-uterine spread and the potential synchronous growth of carcinomas in eutopic endometrium.