Retroperitoneal squamous cell carcinoma involving the pelvic side wall arising from endometriosis: a case report

Introduction: Squamous cell carcinoma (SCC) arising from endometriosis is very rare. Moreover, endometriosis located on the pelvic side wall is uncommon, while its cancerization is quite unusual. We herein report the first case of retroperitoneal SCC arising from endometriosis. Case presentation: A case of 52-year-old woman with retroperitoneal pararectal right mass is presented. The pelvic magnetic resonance imaging showed a retroperitoneal tumor extended to the right pelvic side wall. The neuropelveological examination completed the preoperative assessment, showing a right-sided sciatica and overactive bladder symptoms. Tumor removal was completely managed by minimally invasive technique through laparoscopic laterally extended endopelvic resection (L-LEER) procedure and pelvic neurolysis. Final histology revealed a SCC in a context of diffuse endometriosis with a histologic continuity between the SCC and the endometriosis. The patient underwent adjuvant chemotherapy with no recurrence after six months. Discussion/conclusion: To the best of our knowledge, the present case represents the first evidence of retroperitoneal SCC of the pelvic side wall arising from endometriosis completely resected by laparoscopic approach. Although its rare occurrence, the gynecologist oncologist should maintain a high index of suspicion for malignant endometriosis transformation in case of retroperitoneal pelvic mass and history of endometriosis.