Scar endometriosis: At the drain site following laparotomy

Endometriosis is defined as functioning endometrial tissue (glands and stroma) outside the uterine cavity. It occurs in up to 15% of menstruating women[] and, in most cases, is located within the pelvis. Extrapelvic endometriosis has been described in nearly all body cavities and organs, but its most frequent location is in the abdominal wall.[] Endometrial implants, however, have been reported in many unusual sites outside the pelvis, including the abdominal wall. Abdominal wall endometriosis often develops in previous surgical scars, but there is a case report of a spontaneous occurrence also. Endometrioma is a well-circumscribed mass of endometriosis.[] Majority of the scar endometriosis have been reported after obstetrical or gynecological procedures such as cesarean delivery, hysterotomy, hysterectomy, episiotomy, and tubal ligation, but a few cases are reported following appendectomy, in the laparoscopic trocar tract, and in the amniocentesis needle tract. Its clinical diagnosis in the abdominal wall has been confused with abscess, lipoma, hematoma, sebaceous cyst, suture granuloma, inguinal hernia, incisional hernia, desmoid tumor, sarcoma, lymphoma, or primary and metastatic cancer.[,] We report a case of scar endometriosis developing in the drain site scar post laparotomy for uterine perforation. CASE REPORT A 35-year-old parous woman presented with history of swelling and pain in the right lower abdomen since 5 years. She had undergone dilatation and curettage for mid-trimester abortion, during which there was accidental fundal perforation with sigmoid colon injury, for which an emergency laparotomy with repair of uterine perforation and colostomy was done. Intraperitoneal drain was kept on the right side, which was removed after 48 h. After 3 months, re-laparotomy was performed for closure of colostomy. She noticed swelling at the drain site scar 1 year after the procedure. It was initially small in size, and gradually increased to the present size [Figure 1]. She noticed cyclical increase in pain and size of the swelling. She had congestive dysmenorrhea and menorrhagia since 3 years. There was no history of dyspareunia, bowel and bladder disturbances, or any discharge from the swelling. On abdominal examination, there was a healed vertical midline laparotomy scar and a 6 cm × 6 cm extraabdominal mass in the right iliac fossa at the drain site, which was hard in consistency, mobile, tender to palpate, and with no evidence of cough impulse. On bimanual examination, the uterus was enlarged to 10 weeks' size with restricted mobility. For the above complaints, she underwent ultrasonography of the abdomen, which showed heteroechoic lesion in the anterior abdominal wall with a radiological diagnosis of Desmoid tumor. FNACFine Needle Aspiration Cytology of the swelling showed features suggestive of scar endometriosis [Figure 2]. The patient underwent wide local excision of the scar endometrioma with subtotal hysterectomy and mesh repair of abdominal wall defect. The intraoperative findings were as follows: The post-operative period was uneventful. Histopathology confirmed the diagnosis of scar endometriosis of the mass from the anterior abdominal wall; features of adenomyosis were seen in the hysterectomy specimen [Figure 5].

The first case of scar endometriosis was reported by Meyer in 1903.[] Scar endometriosis is a rare entity in the literature, being described with a frequency of 0.1% in women who have undergone cesarean section. The interval between the surgical procedure and the onset of the symptoms varies between 3 months and 10 years. Concerning the origin of abdominal wall endometriosis, several theories, as follows, have been proposed[,]: A result of transportation and implantation of the endometrial tissue during surgical procedures with subsequent proliferation of the endometrial cells under estrogenic stimulation The theory of “coelomic metaplasia,” which refers to the involvement of peritoneal cells Blood and/or lymphatic spread. This newly formed ectopic tissue undergoes the same cyclical changes as the normal endometrial tissue, changes induced by hormonal stimulation. The endometrioma is characterized by the presence of elements of the endometrial tissue, glands, and stroma. The glands observed microscopically are lined by columnar epithelium. The features of the epithelium vary with the hormonal fluctuations, with the appearance of foci of recent or old hemorrhage, and secondary inflammatory response. Symptoms are usually non-specific, including abdominal pain, nausea, and the presence of an abdominal mass, which may vary in size. All symptoms may sometimes be related to menstrual periods. Some patients rush to the emergency room with severe pain mimicking an acute abdomen, like appendicitis or bowel obstruction. Others may present with non-specific urinary symptoms, which make the clinical diagnosis even more difficult. These non-specific symptoms are the reason why most of the cases are admitted into the surgery unit, although this is a disease concerning the gynecologist. The imaging modalities are non-specific but are useful in determining the extent of the disease and planning of operative resection, especially in recurrent and large lesions. Therefore, FNAC may be the only diagnostic tool in the evaluation of these lesions, providing rapid and accurate pre-operative diagnosis. The treatment modalities for scar endometriosis are medical and surgical. Medical treatment includes combined oral contraceptives, danazol, and Gonadotrophin releasing hormone GnRH analogues. The success rate of medical therapy has been reported to be low, offering only temporary alleviation of symptoms, often followed by recurrence after cessation of the drug.[] Wide excision of the lesion is the treatment of choice. In patients in whom a large defect remains following excision, mesh can be used for repair. These patients need follow-up, as there are chances of recurrence, which can be managed successfully with re-excision.

We should have a high index of suspicion for scar endometriosis when a woman presents with a painful swelling or mass in the abdominal scar, especially with a history of previous gynecological or obstetrical surgery. This condition can be confused with other surgical conditions. Efforts should be made to make a pre-operative diagnosis with imaging techniques. Wide excision is the treatment of choice. Patients should be followed-up for possible recurrence. Source of Support: Nil, Conflict of Interest: None declared.

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