Background. Endometriosis affecting surgical scars is a well-described entity that can complicate surgery involving hysterotomies. Malignant transformation is a rare event that has been reported complicating ovarian endometriosis mainly. Case. A 60-year-old woman having in the past two uneventful caesarean deliveries presented with a solid lower abdominal mass. A surgical biopsy and then a radical resection of the lower half of the abdominal wall were performed, with a diagnosis of adenocarcinoma of endometrial origin. A diagnostic curettage excluded primary endometrial carcinoma. At 1 year she is NED. Conclusion. This case report illustrates the carcinomatous transformation of an endometrial implant. Despite the rarity of such a diagnosis, it should be borne in mind when endometriosis in abdominal wall is suspected because an oncological resection is required. © 2003 Elsevier Inc. All rights reserved