Clear cell carcinoma arising in the abdominal wall: two case reports and literature review

Malignancy in Abdominal Wall Endometriosis: Is There a Way to Avoid It? A Systematic Review

Background: Malignant-associated abdominal wall endometriosis (AWE) is a rare pathology, likely to occur in 1% of scar endometriosis. The objectives of this study were to update the evidence on tumor degeneration arising from AWE to notify about the clinical characteristics, the different treatments offered to patients and their outcomes. Methods: A comprehensive systematic review of the literature was conducted. PubMed, Embase and Cochrane Library databases were used. Prospero (ID number: CRD42024505274). Results: Out of the 152 studies identified, 63 were included, which involved 73 patients. The main signs and symptoms were a palpable abdominal mass (85.2%) and cyclic pelvic pain (60.6%). The size of the mass varied between 3 and 25 cm. Mean time interval from the first operation to onset of malignant transformation was 20 years. Most common cancerous histological types were clear cell and endometrioid subtypes. Most widely accepted treatment is the surgical resection of local lesions with wide margins combined with adjuvant chemotherapy. The prognosis for endometriosis-associated malignancy in abdominal wall scars is poor, with a five-year survival rate of around 40%. High rates of relapse have been reported. Conclusions: Endometrial implants in the abdominal wall should be considered as preventable complications of gynecological surgeries. Special attention should be paid to women with a history of cesarean section or uterine surgery.

Surgery of abdominal wall endometriosis associated with clear-cell carcinoma: Case report and review

Abdominal wall is a rare location for endometriosis, with a reported incidence of parietal endometriosis of approximately 0.03 to 0.4%. It most often occurs in the aftermath of a caesarean section and is associated with pelvic endometriosis in only 5 to 15% of cases. Rare cases of malignant transformation have been described, mainly in the form of clear-cell tumours. We report the case of a 52-year-old patient with a history of endometriosis who presented with a retractile parietal mass at the level of her caesarean scar. Histological analysis confirmed a clear-cell adenocarcinoma (CCC). Few cases of endometriosis - associated CCC are described in the literature. A review of the literature suggests radical surgical treatment combined with adjuvant radio-chemotherapy. However, the prognosis is poor. The aim of this case report is to suggest the diagnosis of malignant transformation in the presence of a rapidly evolving parietal mass in the context of endometriosis and a history of caesarean section.

Clear Cell Adenocarcinoma Arising from Endometriosis in Abdominal Wall Cesarean Section Scar: A Case Report and Literature Review

Background

Endometriosis developing in a cesarean section (CS) scar is an unusual event. Malignant transformation arising on the background of scar endometriosis in the abdominal wall is extremely rare. Herein we report a case of clear cell carcinoma (CCC) arising in the abdominal wall from endometriosis tissues following CS and review previous literature.

Case Presentation

A 48-year-old gravida 2 para 1 female presented with an abdominal wall mass at her CS scar, which increased in size and became painful in the last 2 years. Physical examination showed a multilocular solid mass of about 13 cm, at the previous CS scar. Computed tomography (CT) and magnetic resonance imaging (MRI) revealed a 12.8cm × 7.7cm multi-septate cystic lesion on the anterior abdominal wall, and histological examination showed that CCC was caused by the transformation of abdominal wall endometriosis (AWE).

Conclusion

An endometriosis-associated malignancy should be considered in the differential with any enlarging mass in the abdominal wall scar.

Treatment for clear cell carcinoma of the abdominal wall at a tertiary cancer center

Clear cell carcinoma (CCC) of the abdominal wall is a rare and agressive disease. We aim to elucidate the clinical and prognostic characteristics of this disease. Medical records of ten patients diagnosed with CCC of the abdominal wall at Fudan University Shanghai Cancer Center were reviewed. We illustrate the clinical characteristics, treatment modality, and development of local recurrence or distant metastasis, as well as the survival outcome. The median (range) age of patients was 47 (39-61) years old. All patients had a history of cesarean section and abdominal wall endometriosis. All patients had primary surgery before referred to our center. Seven patients had only tumor resection, while two patients had lymph node metastasis at primary diagnosis. Four patients underwent supplementary surgery, and all postoperative pathology were negative. Genetic analyses had also been performed. The median (range) follow-up time was 20 (12-59) months. Local recurrence and lymph node metastasis were the most common recurrence types. The median (95% confidence interval) PFS was 11 (8.08-13.92) months. In summary, primary surgery should consider wide tumor resection and lymph node dissection. Adjuvant chemotherapy and radiotherapy should be recommended for potential benefits. More cases are still needed to elucidate the clinical management of this disease.

Malignancies Associated with Extraovarian Endometriosis: A Literature Review

Endometriosis-associated ovarian malignancies have been well documented. Although these malignancies also occur as extraovarian lesions, little is known about them. Thus, this literature review aimed to further explore these rarely experienced tumors. A total of 257 published cases between April 1990 and April 2020 were found using PubMed, and 212 cases were included in the analysis considering Sampson’s criteria and the history of endometriosis. We classified these cases as follows: intestine, abdominal scar, vagina and vulva, peritoneum and deep endometriosis, urinary tract, uterine cervix, and others. Age of patients, history of endometriosis, types of past hormonal therapy, symptoms, histological types, and treatment were identified. The most common tumor site was the intestine. Endometrioid carcinoma was the dominant histological type. Contrary to the ovary, clear cell carcinoma was rare in extraovarian sites. On the other hand, clear cell carcinoma represented the largest number of abdominal scars. This difference may help us to understand the development of endometriosis-related malignancies. Hormonal treatment was mentioned in 67 cases and estrogen replacement therapy in 33 cases. Although risks of estrogen therapy are still controversial, the highly differentiated histological types and hormone-dependent characteristics of endometriosis-associated malignancy should be considered. Physicians should be careful about estrogen monotherapy after hysterectomy and long-term hormone replacement therapy in patients with a history of endometriosis.

Malignant transformation of abdominal wall endometriosis: A systematic review of the epidemiology, diagnosis, treatment, and outcomes

Malignant transformation of abdominal wall endometriosis (AWE) is rare. The clinical characteristics and treatment of malignant transformation of AWE are not well known. Therefore, in this review, we performed a thorough search for malignant transformation of AWE on MEDLINE and Web of Science from their inception to May 2021. In total, the data of 46 patients with malignant transformation of AWE were retrieved, and all the data on these patients were collected. After reviewing and analyzing the clinical parameters, we found that cesarean scar was the most common site of malignant transformation of AWE, and the most common pathological type of malignant transformation of AWE was clear cell cancer, followed by endometrioid adenocarcinoma. The main symptoms of malignant transformation of AWE included an abdominal nodule or mass, and ultrasonography was the first choice for diagnosis. The most widely accepted treatment was surgical resection of local lesions with adjunctive chemotherapy and/or radiotherapy, and the overall survival of patients with malignant transformation of AWE was poor. In conclusion, malignant transformation of AWE is rare, and the prognosis is poor. Thus, improving abdominal surgical technology and avoiding iatrogenic ectopia and implantation of the endometrium are necessary to prevent malignant transformation of AWE.

Endometriosis-associated Clear Cell Carcinoma of the Abdominal Wall After Caesarean Section: A Case Report and Review of the Literature

BACKGROUND/AIM

Clear cell carcinoma of the abdominal wall is a sporadic event. To date, about thirty cases have been reported in the literature. This article provides a case report and literature review of an infrequent occurrence with poor prognosis.

CASE REPORT

A 45-year-old woman with pelvic pain and an abdominal mass came to our attention. Her medical history was notable for two previous cesarean sections. Physical examination revealed a smooth, multilocular mass measuring about 20 cm, arising from the previous surgical scar. Histology revealed clear-cell carcinoma resulting from the transformation of abdominal wall endometriosis. Given the disease extent, the patient underwent front-line chemotherapy. After several and multiple chemotherapy regimens, there was a disease progression that resulted in the death of the patient in 7 months. The literature review showed that a previous cesarean section was present in 91% of cases. Besides, approximately 26.5% of women died within 12 months of being diagnosed. The mean age of women was 45.88 years, while the average size of the lesion was 11 cm.

CONCLUSION

Clear cell carcinoma is a rare but occurring event. Middle-aged women showing an abdominal wall mass in close relation with a surgical scar from a previous cesarean section must be promptly investigated. Treatment options usually include surgery and chemotherapy with poor results.

Clear cell degeneration associated with endometriosis of abdominal wall after cesarean section: A case report and systematic review of literature

AIM

The scar of cesarean section (CS) is the most common site of abdominal wall endometriosis (AWE), whose tumor degeneration has been reported in an increasing number of cases; the most frequent histological type is clear cell carcinoma (CCC).

METHODS

We conducted a systematic research of the literature, collecting data regarding the evidence on tumor degeneration from AWE after CS. Moreover, we reported a case of clear cell borderline tumor (CCBT) originating from AWE.

RESULTS

We included data of 37 patients with diagnosis of CCC. The average time between the last CS and the diagnosis of CCC was around 15 years. Overall, 26.0% and 73.9% patients received exclusive local abdominal resection of the lesion and additional surgery, respectively. Lymph nodes involvement was detected in 26.0 % patients and adjuvant chemotherapy was administered in 52.0 % cases. During follow-up period, 15.2% patients died of disease, 32.6% had no evidence of disease, and 17.4% recurred. We diagnosed a CCBT arose in a patients with AWE and a personal history of several surgical procedures for endometriosis, a CS and a subsequent transverse laparotomy. We performed an open bilateral ovariectomy and a large excision of the endometriotic abdominal lesion.

CONCLUSION

Tumor degeneration from AWE seems to be a real occurrence with an increasing number of events. Considering the lack of risk factors and diagnostic instruments for tumor degeneration, the removal of AWE localization could be advisable, even though there was long average time between the trigger surgery and the tumor finding.

Adenocarcinomas presenting as abdominal wall masses

Patients with abdominal wall masses as primary malignant tumours or metastatic disease are rare. Thorough evaluation with biopsy and imaging is required prior to surgical resection for treatment planning. We present a case series of three patients who presented with abdominal adenocarcinoma of unknown primary origin. All patients ultimately underwent surgical resection and final pathology showed a gynaecological origin for these tumours. Multidisciplinary management is required for these rare and complex tumours.

Incisional carcinoma of Mullerian Origin: A case report and review of literature

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Incisional carcinoma is a rare, often delayed, complication of surgery.

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Primary incisional carcinoma can occur in the presence or absence of endometriosis.

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Translocation of benign cells surgery may be a common mode of development.

Primary incisional carcinoma (PIC) is a rare, delayed complication of surgery, usually attributed to the malignant transformation of endometriosis.

We report a case of incisional carcinoma with nodal metastases in a 55-year-old woman, 18 years after cesarean section. She underwent extirpative surgery, including hysterectomy and bilateral salpingo-oophorectomy, without intraperitoneal disease identifed. Adjuvant treatment included sandwiched platinum-based chemotherapy (carboplatin and paclitaxel) and radiation. She remains disease-free 8 months after completing therapy.

We identified 46 additional reported cases. Of these, >90% had undergone an “endometrium-exposing” surgery, most commonly cesarean section; while no cases followed adnexal-only surgery. The median time between antecedent surgery and presentation was 18 years. At presentation, tumors were often large (median 8 cm), and symptomatic with pain (63%) and/or mass (26%). Serum CA125 levels were commonly, albeit slightly, elevated (median 57U/ml (IQR 22–96, Range 6–1690)). Lymph node metastases were common (35%), with most following a vulvar-type spread pattern (inguinal first). Most patients (63%) were treated with chemotherapy +/− radiation. Approximately 50% of patients recurred promptly (median < 6 months), but long-term survival was reported following combined chemotherapy/radiation. Lymph node metastases portended a shorter disease-free interval, with 73% of cases recurring (median 5 months) despite chemotherapy-based treatment.

These data suggest that some incisional carcinomas may result from displacement of healthy endometrium followed by delayed malignant transformation. Chemotherapy-only and radiation-only treatments are attended by modest prognosis. Taken together, these data suggest there is both need and potential avenues for improved prevention, detection, and treatment of this condition.

Abdominal Wall Clear Cell Carcinoma: Case Report of a Rare Event with Potential Diagnostic Difficulties

Clear cell carcinoma (CCC) is a well-known aggressive histological type of carcinoma, predominantly seen in ovary and endometrium. However, CCC arising in abdominal wall is a very rare event. We report a case of a 48-year-old woman with an abdominal wall mass at her cesarean section (c-section) scar, which increased in size and became painful in the last months. Radiology revealed a 7 cm mass in the right inferior rectus muscle sheath, suggestive of endometriosis. An irregular, firm mass was resected, densely adherent to the rectus muscle and pubic bone. Frozen section revealed a multicystic lesion with minimal cytologic atypia, and a benign cystic neoplasm was favored. However, permanent sections showed marked nuclear atypia, hobnail morphology, and areas of infiltrative growth within fibrous stroma. No benign endometrial glands were found, although fibrosis and hemorrhage were present. Napsin-A, racemase, and PAX-8 were positive, consistent with CCC, likely arising within a c-section endometriosis focus. Although CCC usually presents with moderate to marked nuclear atypia, it can be mild and, especially in cases with a predominant cystic pattern, create diagnostic difficulties. An endometriosis-associated malignancy should be considered in the differential with any enlarging nodule or increasing pain within an abdominal wall scar.

Clear Cell Carcinoma of the Abdominal Wall as a Rare Complication of General Obstetric and Gynecologic Surgeries: 15 Years of Experience at a Large Academic Institution

The objective of this article was to report the clinicopathological characteristics, treatment modalities, and outcomes of patients with clear cell carcinoma (CCC) of the abdominal wall. Medical records of six patients diagnosed with CCC of the abdominal wall between May 2003 and May 2018 at the National Taiwan University Hospital were reviewed. All patients had prior obstetric or gynecologic surgeries. The primary clinical presentation was enlarging abdominal masses at previous surgical scars. Four patients underwent initial/primary surgeries with/without adjuvant chemotherapy. One patient received neoadjuvant chemotherapy followed by surgical intervention and adjuvant chemotherapy, the other received chemotherapy and sequential radiotherapy without any surgical intervention. Two of four patients undergoing initial/primary surgeries had disease recurrence and the remaining two cases without initial surgery experienced disease progression during primary treatment. Inguinal lymph nodes were the most frequent sites of recurrence. In conclusion, previous obstetric or gynecologic surgery can be a risk factor for CCC of the abdominal wall. Complete resection of abdominal wall tumor and suspected intra-abdominal lesions with hysterectomy and bilateral inguinal lymph nodes dissection may be the primary treatment. Adjuvant chemotherapy would be considered for potential benefits. For patients without bilateral inguinal lymph nodes dissection, careful inguinal lymph node palpation during postoperative surveillance is necessary. More cases are still needed to elucidate the clinical management of this disease.

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

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.

Endometriosis-associated malignant transformation in abdominal surgical scar: A PRISMA-compliant systematic review

BACKGROUND

Endometriosis-associated malignant transformation in abdominal surgical scar (EAMTAS) is a very rare and aggressive phenomenon. Our current article aims to provide a clinical overview, focusing on risk factors affecting survival.

METHODS

We performed a Preferred Reporting Items for Systematic Reviews and Meta-Analyses-compliant systematic review based on prior reviews and case reports regarding the phenomenon published as abstracts in English, from January 1980 to November 2016. Overall, we identified 47 cases, and we included another case from our institution. We further contacted previous investigators to receive updated follow-up regarding their patients. We analyzed the data, focusing on risk factors that might affect overall survival.

RESULTS

All the patients reported in the literature had a uterine surgery, mainly caesarean section. The median time-lag from first surgery to the diagnosis of cancer was about 19 years. Clear-cell carcinoma (CCC) was the most prevalent histology (67%), followed by endometrioid adenocarcinoma (15%). Most of the patients were treated by extensive surgery and chemotherapy and/or radiation. Overall 5 years survival was about 40%. Median overall survival was 42 months (95% confidence interval of [18.7, 65.3]). Although our review is currently the largest in the literature, we cannot draw any statistical significant results due to the limited number of patients reported. According to univariate Cox-regression models, a tendency toward worse prognosis was shown for 3-year disease-free survival clear cell histologic-type (P = .169), and tumor diameter ≥8 cm in nonclear-cell histology, 18 months postdiagnosis (P = .06).

CONCLUSION

EAMTAS is a rare and aggressive disease. It is mostly related to cesarean section scars and is diagnosed many years postsurgery. Clear-cell histology tends to endure from the worse prognosis. The treatment is mainly extensive surgery and adjuvant chemotherapy and/or radiotherapy.

Clear cell carcinoma arising from scar endometriosis: A case report and literature review

Scar endometriosis is uncommon and defined as the presence of ectopic endometrial glands in abdominal soft tissues after a gynecological operation. Malignant transformation has been reported but remains rare. Carcinogenesis occurs in ectopic endometrial tissue with repeated hormone stimulation during the menstrual cycle. We present a case of clear cell carcinoma directly arising from scar endometriosis after a cesarean section and review all 16 cases reported.

Endometriosis-associated clear cell carcinoma arising in caesarean section scar: a case report and review of the literature

Background

Malignant transformation has been reported in approximately 1% of the endometriosis cases; herein, we report a case of clear cell endometrial carcinoma arising from endometriosis foci located within a caesarean section scar.

Case presentation

In November 2014, a Caucasian, 44-year-old woman was transferred to our institution because of severe respiratory failure due to massive lung embolism and rapid enlargement of a subcutaneous suprapubic mass. Abdomino-pelvic magnetic resonance showed a 10.5 × 5.0 × 5.0 cm subcutaneous solid mass involving the rectus abdominis muscle. Pelvic organs appeared normal, while right external iliac lymph nodes appeared enlarged (maximum diameter = 16 mm). A whole-body positron emission tomography/computed tomography scan showed irregular uptake of the radiotracer in the 22 cm mass of the abdominal wall, and in enlarged external iliac and inguinal lymph nodes. In December 2014, the patient underwent exploratory laparoscopy showing normal adnexae and pelvic organs; peritoneal as well as cervical, endometrial and vesical biopsies were negative. The patient was administered neo-adjuvant chemotherapy with carboplatin and paclitaxel, weekly, without benefit and then underwent wide resection of the abdominal mass, partial removal of rectus abdominis muscle and fascia, radical hysterectomy, bilateral salpingo-oophorectomy, and inguinal and pelvic lymphadenectomy. The muscular gap was repaired employing a gore-tex mesh while the external covering was made by a pedicled perforator fasciocutaneous anterolateral thigh flap. Final diagnosis was clear cell endometrial adenocarcinoma arising from endometriosis foci within the caesarean section scar. Pelvic and inguinal lymph nodes were metastatic. Tumor cells were positive for CK7 EMA, CKAE1/AE3, CD15, CA-125, while immunoreaction for Calretinin, WT1, estrogen, and progesterone receptors, cytokeratin 20, CD10, alpha fetoprotein, CDX2, TTF1, and thyroglobulin were all negative. Liver relapse occurred after 2 months; despite 3 cycles of pegylated liposomal doxorubicin (20 mg/m², biweekly administration), the death of the patient disease occurred 1 month later.

Conclusions

Attention should be focused on careful evaluation of patient history in terms of pelvic surgery, and symptoms suggestive of endometriosis such as repeated occurrence of endometriosis nodules at CS scar, or cyclic pain, or volume changes of the nodules.

Endometriosis-Associated Abdominal Wall Cancer: A Poor Prognosis?

OBJECTIVE

Endometriosis-associated abdominal wall cancer (EAAWC) is rare, and few reports are available. This article provides a review of reports in the literature on the pathology, diagnosis, management, and outcome of patients with EAAWC.

METHOD

We performed a review of existing reports in the English language literature on cancer arising from abdominal wall endometriosis. MEDLINE and EMBASE searches were conducted for articles published from September 1986 to August 2014 using combinations of medical subject heading terms.

RESULTS

We identified 26 articles reporting on EAAWC and added 1 patient who was treated at our institution. In all of these patients, EAAWC was described after uterine surgery (mostly cesarean section). The delay between the first surgery and the diagnosis of malignant disease was more than 20 years. Clear cell carcinoma was the most common histology, followed by endometrioid carcinoma. Death was described in 44% of women within a few months of diagnosis.

CONCLUSIONS

Endometriosis-associated abdominal wall cancer is rare and aggressive. It seems to be associated with cesarean section, and it shows poor prognosis. The mainstay of treatment remains extensive surgery and chemotherapy.

[Clear cell adenocarcinoma arising from abdominal wall endometriosis]

BACKGROUND

Clear cell carcinoma originating in the abdominal wall is a rare event. It is generally associated with endometrial tissue implants left behind after a caesarean section or other gynaecological operations. Its pathophysiology is complex and controversial.

CLINICAL CASE

The case is presented of a 45 year-old female with history of three caesarean sections, who was seen due to having a tumour mass of 6 months onset in the anterior abdominal wall. Imaging studies confirmed its location, and due to measuring 9 by 7 cm it was suspected to be an urachal tumour. A resection with wide margins was performed. The histopathology report was of a clear cell adenocarcinoma originated in ectopic endometrial tissue, with negative margins.

CONCLUSION

This is a very rare case, with few cases reported in the literature. This diagnosis should be included in tumours of the abdominal wall.

Maternal caffeine consumption and small for gestational age births: results from a population-based case-control study

Caffeine is consumed in various forms during pregnancy, has increased half-life during pregnancy and crosses the placental barrier. Small for gestational age (SGA) is an important perinatal outcome and has been associated with long term complications. We examined the association between maternal caffeine intake and SGA using National Birth Defects Prevention Study data. Non-malformed live born infants with an estimated date of delivery from 1997-2007 (n = 7,943) were included in this analysis. Maternal caffeine exposure was examined as total caffeine intake and individual caffeinated beverage type (coffee, tea, and soda); sex-, race/ethnic-, and parity-specific growth curves were constructed to estimate SGA births. Crude and adjusted odds ratios (aORs) and 95% confidence intervals were estimated using unconditional logistic regression. Interaction with caffeine exposures was assessed for maternal smoking, vasoconstrictor medication use, and folic acid. Six hundred forty-eight infants (8.2%) were found to be SGA in this analysis. Increasing aORs were observed for increasing intakes of total caffeine and for each caffeinated beverage with aORs (adjusting for maternal education, high blood pressure, and smoking) ranging from 1.3 to 2.1 for the highest intake categories (300+ mg/day total caffeine and 3+ servings/day for each beverage type). Little indication of additive interaction by maternal smoking, vasoconstrictor medication use, or folic acid intake was observed. We observed an increase in SGA births for mothers with higher caffeine intake, particularly for those consuming 300+ mg of caffeine per day. Increased aORs were also observed for tea intake but were more attenuated for coffee and soda intake.

Clear cell carcinoma arising from cesarean section scar endometriosis: case report and review of the literature

Introduction. The incidence of endometriosis affecting skin tissue represents only 0.5–1.0% of all endometriosis cases. A malignancy in the abdominal wall arising from endometriosis following cesarean section is even rarer; only 21 cases have previously been reported. The therapeutic strategy has not been determined because of the limited cases. We report a case of clear cell adenocarcinoma arising in the abdominal wall from endometriosis tissues following cesarean section and review previous literature to achieve the optimal treatment and better prognosis. Case Presentation. A 60-year-old woman presented with a growing mass at the left side of a cesarean section scar. Radical resection of the abdominal wall mass was performed. Histopathological examination showed a clear cell adenocarcinoma. Benign endometrium-like tissues were found adjacent to the cancer lesion in the excised specimen, suggesting malignant transformation from endometriosis of the abdominal wall. Discussion. Local resection was performed in 10 cases (47.6%) and total abdominal hysterectomy or oophorectomy was conducted in 11 cases (52.4%). No malignant lesions were observed in either the uterus or adnexa that were resected. These cases may be expected to increase with increasing incidence of cesarean section. The significance of the extensional resection should be further elucidated.

Novel insights on the malignant transformation of endometriosis into ovarian carcinoma

The malignant transformation of endometriosis is an uncommon event, which happens in 0.7-2.5% of the cases, and, when occurs, it usually involves the ovary. A 2 to 3-fold higher risk of ovarian endometrioid and clear cell carcinoma has been reported in women with endometriosis. Pathological studies have detected a morphological continuum of sequential steps from normal endometriotic cyst epithelium to atypical endometriosis and finally to invasive carcinoma. Ovarian endometrioid carcinoma harbors mutations of CTNNB1 in 16-53.3%, of PTEN in 14-20% and of ARID1A in 30-55% of the cases. Ovarian clear cell carcinoma harbors mutations of PIK3CA in 20-40% and of ARID1 in 15-75% of the cases. Whereas estrogen receptors and progesterone receptors are quite always absent, HNF-1b is often over-expressed in this histotype. Atypical endometriosis and endometriosis-related ovarian neoplasms share molecular alterations, such as PTEN mutations, ARID1A mutations and up-regulation of HNF-1b. Moreover, ARID1A mutations have been noted in clear cell tumors and contiguous atypical endometriosis, but not in distant endometriotic lesions. The loss of BAF250a protein expression is suggestive for the presence of ARID1A mutations, and represents an useful marker of malignant transformation of endometriosis.