Primary endometrioid adenocarcinoma arising on vaginal endometriosis: a case report and review of the literature

Background: Malignant transformation of extragonadal endometriosis is a rare event, mostly described in surgical scars endometriosis or bowel endometriosis. We here present the case of a 59 years old patient, with endometriosis and malignant transformation of a vaginal endometriotic nodule. A systematic review of the literature was conducted to analyze evidence about malignant transformation of vaginal endometriosis and its related treatments. Methods: A detailed description of the surgical procedure is reported. Data regarding patient's characteristics were recorded. Operative data including operative time (min), estimated blood loss (mL), occurrence of intraoperative and postoperative complications within 30 days from surgery were registered. Oncological outcomes refer to a 36 -month follow-up. We conducted a systematic review of the online medical databases Ovid MEDLINE, EBM Reviews Cochrane Central Register of Controlled Trials and Cochrane Database of Systematic Reviews by May 2023 using the following keywords "endometriosis, endometrioid" and "malignant transformation" or "carcinoma, tumor, neoplasm" and "vagina, rectovaginal". Results: A nerve -sparing laparoscopic total hysterectomy with bilateral salpingo-oophorectomy and en -bloc posterior upper colpectomy was performed. No postoperative complications within 30 days from surgery occurred. Final histology confirmed grade 2 adenocarcinoma arising from endometriotic lesion. Adjuvant chemotherapy was administered. The 36 -month clinical follow up was uneventful. After the exclusion of the studies on carcinomas arising in different sites, a total of 23 eligible studies were identified and included in the systematic review. In case of confined vaginal disease, exclusive surgical treatment was reported in 7 (30.4%) studies, while surgery followed by chemotherapy was reported as effective treatment in 10 (43.5%) studies. Five (21.7%) studies suggested external beam radiation therapy as adjuvant option. In 3 (13%) cases exclusive chemo-radiation treatment was proposed. Conclusions: Vaginal malignancies arising on endometriosis represent an extremely rare disease and it is difficult to establish a standard treatment. This study showed the feasibility of the laparoscopic approach to perform surgery, with a detailed description of the surgical technique. The results of the studies included in the review are characterized by heterogeneity, but the surgical excision represents the most common treatment. Adjuvant chemotherapy or radiation therapy may represent an option in relation with the characteristics of the patients and the extension of the disease.