Abstract:

A Collision tumor refers to the coexistence of two or more primary tumors of distinct histological origins in the same anatomical site without mutual transition. We report a rare case of an advanced high-grade endometrial stromal sarcoma coexisting synchronously with endometrioid adenocarcinoma. The patient was a 51-year-old female admitted with lower abdominal distension and pain. Imaging revealed a large solid pelvic mass accompanied by multiple organ metastases, invasion of the inferior vena cava, and suspected tumor thrombus. Postoperative pathology confirmed high-grade endometrial stromal sarcoma (stage ⅣB) combined with well-differentiated endometrioid adenocarcinoma. Genetic testing indicated a TP53 mutation. Despite undergoing cytoreductive surgery and adjuvant chemotherapy, the patient developed recurrence at the vaginal stump and widespread tumor progression approximately two months after surgery. Through analysis of this case and literature review, we suggest that for pelvic tumors presenting with complex imaging features, extremely rapid clinical progression, and extensive involvement, the possibility of rare pathological combinations should be considered. This case also highlights the urgent need to develop individualized therapeutic strategies based on molecular subtyping to improve the prognosis of such patients.

Key words: Sarcoma, endometrial stromal, Endometrial neoplasms, Carcinoma, Collision tumor, Multi-disciplinary team, Therapy