Endometriosis of the rectus abdominis muscle after Caesarean section

Background: Abdominal wall endometriosis is a rare entity, which is usually caused by grafting of endometrial cells to the abdominal wall during laparotomy for pelvic surgery, particularly Caesarean section. Methods: We report on a case of an endometriosis of the rectus abdominis muscle, 5 years after Caesarean section. Results: A 32-year-old woman presented with a palpable, tender nodule of 4-cm diameter in the lower right abdomen, 5 years after Caesarean section. The patient claimed that the lesion became more painful during menstruation, and that it gained significant size during the last 6 months. The CT of the abdomen showed that the tumour was situated between the two leafs of the rectus sheath and was attached to the rectus abdominis muscle. A wide resection of the tumour was performed including the surrounding fibres of the rectus abdominis and the covering fascia of the rectus sheath. The histological examination of the specimen revealed the presence of ectopic endometrial tissue. Conclusions: Endometriosis of the abdominal wall is extremely rare but the clinician has to keep it in mind for the differential diagnosis of abdominal wall tumours.