Active surveillance of an endometriosis-related, hormone-responsive pelvic adenosarcoma during pregnancy: A case report

Background: Extrauterine adenosarcomas are rare gynecologic malignancies that can arise within foci of pelvic endometriosis. They are often hormone mediated and thus are challenging to treat during pregnancy. Case presentation: We present the case of a hormone-receptor positive extrauterine adenosarcoma arising within a known focus of pelvic endometriosis diagnosed in the second trimester of pregnancy. The posterior pelvic mass involved and completely obstructed the colon. The patient desired pregnancy continuation and was managed with surgical intestinal diversion followed by serial surveillance with MRI imaging. Indicated primary preterm cesarean delivery was performed at 30 weeks gestation, after which she was treated with dual anti-estrogen therapy followed by definitive surgical resection. Fifteen months after surgery, she remains free from disease. Conclusion: We review salient topics including malignant transformation of endometriosis, hormone therapy for adenosarcoma without sarcomatous overgrowth, and ethical considerations of cancer management during pregnancy.