Malignant transformation of abdominal wall endometriosis to clear cell carcinoma: case report

ABSTRACT BACKGROUND: Malignant transformation of endometriosis in the abdominal wall is a rare and still poorly understood event. Less than 30 cases have been reported in the worldwide literature. Most cases of solid tumors are report in a previous abdominal scar with malignant transformation of a focus of endometriosis. Presence of lymph node metastases in nearby chains is frequent and is associated with poor prognosis. CASE REPORT: We report a case of a 42-year-old woman with a history of abdominal surgery (Pfannenstiel) to resect abdominal wall endometriosis. Physical examination revealed a solid mass of approximately 10 cm x 6 cm in the anterior wall of the abdomen. Computed tomography (CT) of the abdomen and pelvis showed a heterogeneous, predominantly hypoattenuating expansive formation measuring 10.6 cm x 4.7 cm x 8.3 cm. The patient underwent exploratory incisional laparotomy, block resection of the abdominal mass and lymphadenectomy of the external and inguinal iliac chains. The abdominal wall was reconstructed using a semi-absorbable tissue-separating screen to reconstitute the defect caused by resection of the tumor. Histological evaluation revealed infiltration by malignant epithelioid neoplasia, thus confirming the immunohistochemical profile of adenocarcinoma with clear cell components. Lymphadenectomy showed metastatic involvement of an external iliac chain lymph node. CONCLUSION: Resection of the mass along with the abdominal wall, with wall margins, is the most effective treatment. Reconstruction is a challenge for surgeons. The patient has been followed up postoperatively for eight months, without any evidence of disease to date.


INTRODUCTION
Endometriosis is defined as the presence of stroma and endometrial glands outside the uterine cavity.It affects approximately 15-40% of women of childbearing age.The most common site is the abdominal cavity, specifically in the pelvis and occasionally at extra-pelvic sites. 1,2bdominal wall endometriosis accounts for 0.4-2% of the cases, and is mostly found in the umbilical scar and in the scar of previous abdominal incisions, especially in cesarean scars, laparoscopies and appendectomies. 2 patients with abdominal wall endometrioma, the mean time taken to reach the diagnosis is 6 to 20 years after the initial surgery, and 14.3-26% of the cases show an association with pelvic endometriosis. 2 The endometrioma is diagnosed preoperatively only in 20-50% of the cases, and the typical complaint is most frequently cyclical menstrual pain.The differential diagnoses for an abdominal mass associated with a previous surgical incision in the abdominal wall include abscess, hematoma, hernia, desmoid tumors, sarcomas and metastatic disease. 1 Malignant transformation of an abdominal wall endometrioma is an extremely rare event.
Extensive local excision with surgical margins seems to be the only effective treatment, and it is almost always necessary to correct the defect of the abdominal wall with prosthetic surgical or cutaneous flaps for the closure of the abdominal wall.
Here we report a case of abdominal wall endometrioma that evolved into clear cell carcinoma of the abdominal wall with metastases to the lymphatic system.by resection of the tumor, using a semi-absorbable tissue-separating screen composed of a polypropylene parietal face and a visceral face coated with carboxymethyl cellulose.This rectangular sodium hyaluronate mesh measured 20.3 cm x 30.5 cm (Sempramesh IP Composite Bard Davol Inc.).Histological analysis on the abdominal mass revealed infiltration by malignant epithelioid neoplasia into soft tissues, thus confirming the immunohistochemical profile of adenocarcinoma with clear cell components (Figure 3).The antigens investigated in the immunohistochemical evaluation are listed in Table 1.Lymphadenectomy showed metastatic involvement of an external iliac chain lymph node (1/8), and that other

CASE REPORT
The patient was a 42-year-old female, with one previous pregnancy, with a history of cesarean section seven years previously and resection of endometriosis of the cephalic scar (Pfannenstiel) two years previously at another service, for which a histopathological diagnosis of abdominal wall endometriosis was made.
Her condition evolved with progressive expansion in the region   lymph nodes of the iliac and inguinal chains presented lymphoid hyperplasia (0/11).
Our patient is in her second postoperative month, without having presented any clinical or surgical intercurrence to date.
She is being followed up by the oncology sector and an adjuvant chemotherapy scheme has been indicated.

DISCUSSION
Malignant transformation of endometriosis is quite rare and affects less than 1% of the female population suffering from this condition.
In the literature, the most common site of malignant transformation of endometriosis foci is the ovaries, while 20% of the cases occur at extragonadal sites, including the rectovaginal septum, colon and distal organs such as the abdominal wall.Less than 5% of these cases are carcinomas of clear cell origin like the case reported here. 3is malignant transformation in the abdominal wall is an extremely rare event, with less than 30 case reports in the worldwide literature.These cases consisted of endometrioid carcinoma (70%), sarcoma (25%) and clear cell carcinoma (5%). 4mpson was one of the first authors to report a case of malignancy of an endometriosis outbreak.He proposed three criteria for diagnosing malignant transformation of endometriosis: 1. Demonstration of neoplastic and benign endometrial tissue in the tumor; 2. Histological type compatible with endometrial origin; 3. No other primary site identified. 5 1953, Scott added a fourth criterion: histological presence of benign endometriosis and carcinoma with glandular transformation with atypias.Few reported cases have met all four proposed criteria, and the etiogenesis of such cases remains unknown. 6lignancy of a focus of endometriosis on a previous scar on the abdominal wall is very rare, with a reported prevalence of 0.03%.
It can affect all layers of the abdominal wall and the growth of such masses is exponential, reaching diameters greater than 10 cm. 7n our case, the mass appeared in the anterior wall of the abdomen without evidence of abdominal cavity involvement from abdominal CT.The abdominal wall itself was limited by the peritoneum.Our patient underwent preoperative screening for a primary focus of neoplasia, by means of upper gastrointestinal endoscopy, colonoscopy and thyroid ultrasonography.All of these were negative for neoplasms.
We reviewed the literature through MEDLINE, PubMed, Embase and LILACS using the English keywords "endometriosis", "cell transformation", "adenocarcinoma" and "abdominal wall".
We found only 17 reports, as shown in Table 2, and 15 reports had clinical presentation similar to the reported case.Table 3 7-21 lists the reports in the literature describing the different types of treatment for clear cell carcinomas of the abdominal wall that were derived from an endometrioid focus on a previous abdominal scar.
Local invasion is an important biological feature for transformation of endometriosis into invasive carcinoma.[9] At the time of the pre-surgical evaluation, it was difficult to make a diagnosis of lymph node involvement.However, the presence of lymph node enlargement in the inguinal region and in the external iliac chain was observed on CT scans.This was investigated using computerized tomography with 18-fluorodeoxyglucose positron emission tomography (FDG-PET).
Presence of a compromised lymph node in the 2-cm external iliac chain was demonstrated, with standardized uptake values (SUV) for the abdominal mass of 4.16 and 2.51 in the iliac lymph node.There were no other signs of FDG uptake.
In our case, lymphadenectomy of the external and inguinal iliac chain was performed, and the metastatic involvement of the lymph node caused by carcinoma was confirmed through histological analysis.Radical resection is considered to be the primary treatment for endometrioid carcinoma of the wall.Carboplatin-based chemotherapy and radiation therapy schemes have been proposed without any evidence of improved prognosis or survival. 7e to the rarity of this tumor, the long-term survival following treatment is unknown.However, some recent reports have shown that aggressive radical surgery with total tumor excision with free margins, together with lymphadenectomy of the inguinal and iliac chains may be beneficial for these patients' disease-free survival.

CONCLUSION
Malignant transformation to clear cell carcinoma from a focus of endometriosis on the abdominal wall is a rare and poorly understood complication.Most recent studies have shown that aggressive surgical resection with safety margins associated with lymphadenectomy is still the most effective treatment with the highest survival rates.The role of adjuvant therapy remains unclear and therefore further studies to assess the long-term benefits are required.
In our case, lymphadenectomy of the external and inguinal iliac chain was performed, and the metastatic involvement of the lymph node caused by carcinoma was confirmed through histological analysis.Resection, R-Ad 48 Death Sergent et al. 13 (a) HTA + SOB, Q-Ad 9 Death Alberto et al. 14 (a) Resection, Q-Ad, R-Ad NA Not reported Rust et al. 15 Resection NA Not reported Bats et al. 7 (a) Q-Neo, Resection, HTA + SOB NA Not reported Razzouk et al. 16 (b) Resection, Q-Ad 6 Death Williams et al. 17  Resection, HTA + SOB, Q-Ad 11 Death Yan et al. 18 Resection, Q-Ad 24 Alive without evidence of disease Mert et al. 19

Figure 1 .
Figure 1.Computed tomography scan of the abdomen and pelvis (portal phase) showing an expansive process in the anterior abdominal wall and pelvis and lymph node enlargement in the external and inguinal iliac chains.

Figure 2 .
Figure 2. Macroscopic appearance demonstrating areas of cystic and trabecular components.

Table 1 .
Immunohistochemical profile and antigens investigated

Table 2 .
Search of the literature in medical databases for cases of degeneration of abdominal wall endometriosis for clear cell carcinoma.(Searchwas conducted onApril 14, 2017)

Table 3 .
Reported cases of clear cell carcinoma of the abdominal wall derived from focus of endometriosis