A rare case of concomitant endometrioid adenocarcinoma arising from uterine adenomyosis and clear cell carcinoma arising from parametrial deep endometriosis.

Background: Carcinomatous changes from the ectopic endometrial glands in endometriosis have been reported in many studies, but malignant transformation from uterine adenomyosis/adenomyoma is rare. And clear cell-like adenocarcinoma represents a seldom-encountered malignant pathological variant of ectopic endometrium.

Case Presentation: This case report presents a case of a 44-year-old nulliparous woman begun with abdominal pain and intestinal obstruction. Past medical history showed laparoscopic ovarian endometriotic cyst excision. Ultrasound indicated adenomyoma and a parametrial hypoechoic nodule with abundant blood flow signals and unclear boundaries. Deep invasive endometriosis was considered preoperatively. The patient underwent laparoscopic subtotal hysterectomy and bilateral adnexa resection. Chocolate cyst-like lesion was observed in the parametral lesion. Postoperative pathological examinations suggested endometrioid adenocarcinoma arising from eutopic endometrium and adenomyoma. Ectopic endometrium in the myometrium combined with atypical hyperplasia and formation of endometrioid adenocarcinoma. Left parametrial lesions suggested poorly differentiated endometrioid adenocarcinoma combined with clear cell carcinoma. CD10 + endometrial stromal cells were observed surrounding tumor cell masses. Combined with surgical founding and pathological characters of the left parametrial adenocarcinoma, the parametrial lesions were more likely to be carcinomatous changes of the original deep endometriosis.The patient underwent subsequent transabdominal tumor cell reduction surgery and chemotherapy.

Conclusion: We herein present a rare case of combined endometrioid adenocarcinoma arising from uterine adenomyosis and clear cell carcinoma arising from parametrial deep endometriosis that may help inspire additional studies in the future. The patient underwent robot-assisted laparoscopic subtotal hysterectomy, bilateral adnexa resection, deep endometriosis lesion resection and bilateral ureteral stent placement. Following surgery, a chemotherapy regimen of Taxol and Carboplatin was administered.