Description

A 28-year-old woman, para 2, with two previous caesarean sections, presented with pain and swelling in lower abdomen at the caesarean scar site for 6 months. The last caesarean section was performed 2 years earlier. There was no history of cyclical pain. On examination, a 3×2 cm irregular, nodular, dark coloured, firm, immobile swelling was present on the lateral end of the caesarean scar (figure 1). The patient's general, systemic and gynaecological examination revealed no abnormality. Pelvic ultrasound detected no abnormality but in the region of the lesion it showed presence of discrete solid nodules with irregular borders surrounded by a hyperechoic rim. Differential diagnoses of scar endometriosis and stitch granuloma were made. Excision of the mass was planned. Perioperatively the lesion extended to the rectus sheath. The whole mass was excised with wide margins including the part of the rectus sheath that was involved (figure 2). Histopathological examination showed the endometrial glands mixed with stroma in fibroadipose tissue confirming the diagnosis of scar endometriosis.

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Figure 1

Lower abdominal wall showing scar endometriosis in the region of caesarean section scar.

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Figure 2

Tissue removed after excision.

Scar endometriosis is an extremely rare condition with an incidence of 0.03–0.4% and usually occurs after caesarean section.1 The interval between the surgery and the manifestation varies from 3 months to 10 years postoperatively. Swelling and pain are the most common symptoms. History of cyclical pain may be present. The differential diagnoses of such swelling include haematomas, stitch granulomas, neuromas, abscess and malignancy. Different diagnostic modalities available are ultrasonography, CT and MRI; these modalities generally guide as to depth and extent of lesion and help in planning excision. Needle aspiration cytology can also be performed before surgery if there is a suspicion of malignancy although patient history and the appearance of swelling are very much indicative of the diagnosis. Wide excision with removal of all the endometrial tissue is the treatment of choice.

As the pathogenesis of scar endometriosis is direct inoculation during surgery,2 it is recommended to follow good surgical technique during caesarean section and irrigation of the incision site before abdominal wall closure and to use separate sponges for cleaning the uterine cavity and skin wound.