Abdominal wall endometriosis: Report of 83 cases

To investigate the clinical course and management of abdominal wall endometriosis (AWE).


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BENEDETTO ET al. surgery. The etiology of the latter type of AWE may be due to the direct implantation of endometrial cells into the soft tissues of the abdominal wall, via an iatrogenic process during abdominal-pelvic surgeries. 6 It has been reported that 57%-92% of these cases develop secondary to cesarean section. 7 The reported incidence of AWE varies from 0.03 to 3.5%, 8,9 and the reported incidence of AWE within the cesarean section scar is 0.03%-0.45%. 1,10 Nevertheless, the disease is probably underdiagnosed.
Mean age at diagnosis is 33.2-35 years, 11,12 and the elapsed time between the previous surgery and the diagnosis of secondary AWE may vary from 3 months to two decades. 9 The characteristic clinical triad includes: mass in the abdominal wall or nodule at the previous scar, cyclic pain related to the menses, and history of a previous abdominal surgery. [13][14][15] Depending on the layer of the abdominal wall affected, skin changes (ecchymosis or hyperpigmentation), swelling and bruising of the surgical scar associated with the menstrual cycle may be observed. [16][17][18] Ultrasound and magnetic resonance imaging of the pelvis and abdomen, including the abdominal wall study, play an important role in the diagnosis. 1,15 Wide surgical excision is the only curative therapy of AWE. 1,10 The final and precise diagnosis is given by histological analysis of the nodule. 17 The aim of this paper is to investigate the clinical course and management of AWE. Pain complaint was quantified using the Visual Analogue Scale, giving a score from 1 to 10. The pain was considered mild to intermediate when the score ranged from 1 to 6 and intense when it ranged from 7 to 10.

| MATERIAL S AND ME THODS
Preoperative work-up included abdominal ultrasound or pelvic/ abdominal MRI, depending on each specific situation ( Figure 1).

| SURG IC AL PROCEDURE
Overall, the main objective of the surgery was to entirely remove the nodule, including the surrounding fibrosis, in order to reduce the recurrence rate.
The role of the radiologist was very important for non-palpable nodules. They were located by 2 different ways: • Abdominal wall ultrasound on the day before surgery. In this case, the skin right above the nodule was marked using a pen; • Intraoperative abdominal wall ultrasound.
For umbilical nodules, the darkened tone of the navel skin was an indicator for the need for skin excision along with the nodule.
Whenever complete excision of the umbilicus was necessary, reconstruction using a skin graft with the help of a plastic surgeon was performed ( Figure 2). Partial infiltration of the navel skin was treated with partial umbilical preservation and reconstruction ( Figure 3).
For implants secondary to laparoscopic ancillary port placement, the incision was performed over the nodule.
For the remaining cases, an incision was performed over the previous Pfannenstiel incision and dissection was carried out down to the level of the nodule. Nodules might be located at the subcutaneous fatty tissue, aponeurosis, abdominis rectus muscle, and/or peritoneum. During surgery, the nodule was resected completely regardless of the affected layer of the abdominal wall.
Usually, nodules greater than 50 mm diameter which infiltrate the aponeurosis generally required reconstruction of the abdominal wall using mesh ( Figure 4). Small nodules affecting the aponeurosis, nodules affecting only the subcutaneous fatty tissue, and nodules affecting below the aponeurosis (abdominis rectus muscle with or without peritoneum) were usually reconstructed without the need for mesh placement.   Of the total of 83 patients, five of them (6%) had already been submitted to a previous AWE resection in another service and recurred.
Umbilical nodules were not big enough to require reconstruction with meshes. In all cases the aponeurosis was closed using interrupted sutures of zero polyglactin 910 suture or zero polydioxanone suture. Only one patient required complete excision of the whole umbilical scar and reconstruction using a skin graft.
One patient had a left lower quadrant cystic implant, arising exactly at the site of placement of the 5 mm ancillary port during the previous laparoscopic procedure.
Seventeen nodules were bigger than or equal to 30 mm of diameter. In five cases of nodules bigger than 50 mm reconstruction using mesh was performed.
In one case, a large nodule measuring around 100 mm was identified by MRI and seemed to infiltrate the peritoneum and the abdominis rectus muscle, without infiltration of the aponeurosis. This was the only patient operated by laparoscopy ( Figure 5). In this case there was no need for mesh placement. In Routinely, an abdominal ultrasound was performed to evaluate the results of the surgery and check for any persistence of the disease 6 months after surgery. In the case of a negative imaging exam, abdominal ultrasound was performed annually to detect recurrence.
We did not find any persistence or recurrence of the disease in our series up to now.

| DISCUSS ION
In this paper the authors report a series of 83 patients undergoing surgery for abdominal wall endometriosis. Primary AWE occurs at the umbilicus and corresponded to 24.1% of the cases in the series.
The remaining cases (75.9%) were secondary implants of AWE developing after cesarean section or laparoscopic procedures.
It has been reported in the literature that 57 to 92% of the cases develop secondary to cesarean section. 7,11 Recently, Marras et al.  Cyclical pelvic pain and subfertility may also be present. [17][18][19] In a study including 198 patients with cesarean scar endome- There seems to be an association between the occurrence of AWE and the presence of raised body weight (BMI ≥25 kg/m 2 ). In our series, the mean BMI was 25.2 kg/m 2 . Some authors have already showed a predominance of raised body mass in patients diagnosed with AWE (25.5 to 29.2 kg/m 2 ) and have justified this relationship due to the technical difficulties in operating obese patients, probably related to inadequate hysterorrhaphy. 22,23 Differential diagnoses include sarcomas, metastatic malignant tumors, granulomas, abscess, sediment, incisional hernia, hematoma, desmoid fibromatosis and lipoma. The histological examination of the tumor can state the precise diagnosis and exclude malignancy. 12,17 The treatment of choice is the complete excision of the endometriotic nodule. Some authors recommend a 5 to 10 mm margin-free excision to prevent recurrence. 7,21 In cases of a non palpable nodule, the demarcation of the lesion guided by ultrasound in the preoperative setting can help to determine the exact location of the nodule during surgery.

TA B L E 2 Data according to the main clinical characteristics and previous surgical history of the patients with AWE
In cases affecting the aponeurosis, when there may be tension in the suture line or in cases of nodules larger than 50 mm, extensive mobilization of the aponeurosis and placement of a polypropylene prosthesis may be recommended. It may be essential for successful tension-free closure of the abdominal wall. 12,24 In our series, we used mesh for abdominal wall reconstruction only for nodules bigger than 50 mm infiltrating the aponeurosis. However, two out of eleven The risk of AWE recurrence varies between 12.5% and 28.6%. 25 In our study 5 patients (6%) were operated due to a recurrent AWE nodule. All of them had their first surgical procedure in another service. In our experience, the main issue during surgery is to remove completely the nodule and the fibrotic tissue around it. Similar to pelvic endometriosis, the fibrotic tissue around the nodule may contain endometrial tissue and may be the place from where recurrence of the nodule starts.
During gynecological/obstetric surgical procedures, some practices can be useful to avoid implantation of endometriosis in the abdominal wall. We suggest the use of wound protectors/retractors in all cesarean sections, which seems to be the main risk factor for the de- This study has some strengths, including the high number of cases, the fact that all the procedures were performed by the same surgeon, and the apparent good surgical technique with no recurrences. The main limitation of the study was the retrospective nature of data collection and some missing data.

| CON CLUS ION
In conclusion, abdominal wall endometriosis is a rare and uncommon pathologic condition, with higher risk in women with a previous history of cesarean section. AWE should be considered as an important differential diagnosis in women suffering from a cyclical painful nodule or mass close to or at the site of the surgical incision. Wide

DATA AVA I L A B I L I T Y S TAT E M E N T
Research data are not shared.