Introduction/Background Adenomyosis is usually benign, but it might also be a precursor of malignant disease. As the incidence of adenomyosis malignant transformation is low, and its clinical manifestations are nonspecific. It may only be confirmed by postoperative pathological examination. We report our experience with case of malignant transformation of adenomyosis with endometrial adenocarcinoma.

Methodology This retrospective study was examined using data at Uijeongbu St. Mary’s Hospital from the 2014 to 2018. A total of 27 women has endometrial cancer combined adenomyosis or endometriosis. Ant Only one person has related with elevated CA19-9.

Results Sixty-two years-old nulliarous woman visited our department at Jan 2019 due to intermittent vaginal bleeding over 1 month. Ultrasound showed hematometra and adenomyosis. The histological examination of the endometrium yielded adenocarcinoma, moderately differentiated. Magnetic resonance imaging (MRI) revealed focal adenomyosis, hematometra and a few small nonspecific LNs in right external iliac and obturator. Among the pre-operative tumor markers, CA19-9 level was increased (36.80U/ml, normal range <35U/ml). But CA125 was within normal range (19.90 U/m, normal range <35U/ml).

Laparoscopic total hysterectomy and bilateral adnexectomy including pelvic lymphadenectomy were performed. The intra-abdominal cytology was negative. In the pathological specimen, poorly differentiated endometrioid adenocarcinoma was present in endometrium with myometrial invasion less then 0.1 cm from endometrial-myometrial junction (T1a, thickness of uninvolved myometrium was 1 cm). Pelvic lymph node metastasis was not found. Very small Foci of adenocarcinoma were observed in adenomyosis (0.1 × 0.1 sized). Although surgical stage was Ia, due to the histologic grade and high risk factors (>60 yrs), recurrence risk was existed. Adjuvant vaginal brachytherapy was performed after surgery. She is currently undergoing follow-up observations.

Conclusion From this case, we concluded that if CA19-9 is elevated before surgery, a more detailed histological observation is needed in the adenomyotic foci.

Disclosure Adenomyosis, endometrial carcinoma, CA 19-9, malignancy.