Clear cell carcinoma with lung metastasis arising from endometriosis in the abdominal surgical scar - management with a multidisciplinary mode

A 56-year-old woman was transferred to our department because of rapid growth of a subcutaneous suprapubic mass. She had had a cesarean section (CS) with tubal ligation 30 years prior. Physical examination revealed an irreducible and firm mass arising from the subcutaneous tissue of the previous CS scar, while whole body computerized tomography (CT) showed a subcutaneous solid mass of 11 × 7.4 × 7.6 cm in the anterior abdominal wall (Fig. 1A) and a speculated nodule of 1.7 cm in the left lung (Fig. 1B), respectively. Subsequently, a biopsy revealed a metastatic carcinoma likely originating from the kidney, thyroid or gynecological organs, so a wide resection of the abdominal mass was performed in addition to radical hysterectomy with bilateral salpingo-oophorectomy. Histological examination of the specimen revealed high-grade clear cell carcinoma (CCC) arising from endometriosis foci within CS scar (Fig. 1C). Immunohistochemically, tumor cells were positive for PAX8, HNF1b and weak staining for Napsin (Fig. 1D). Two weeks later, a videoscopic segmentectomy for the left lung lesion was performed, which demonstrated a metastatic CCC pathologically. Postoperative adjuvant chemotherapy with carboplatin and paclitaxel has been administrated for 6 months. She remains alive two years post-surgery. The incidence of malignant transformation of endometriosis is currently estimated to be 0.7–1.5% [1–3]. The ovary is most frequently affected but the abdominal wall is rarely implicated [1–3]. Most of these patients have usually had uterine surgery previously, mainly caesarean section, with an approximate mean lag-interval of 20 years from the time of surgery [1–3]. Although the exact mechanism of malignant transformation of endometriosis remains unclear, recent research reveals that the redox cycling of the great amount of free iron present in endometriotic cysts could lead to generation of reactive oxygen species (ROS), oxidative stress and DNA mutations that ultimately enhance carcinogenesis [2]. CCC (66%) constitutes the predominant histological subtype followed by endometrioid carcinoma (24%) in patients with malignant endometriosis involving the abdominal wall [1–3]. Imaging studies including CT, magnetic resonance imaging (MRI) and PET are helpful to delineate the extent of disease and distant metastasis with the most frequent site of metastasis being the inguinal lymph node while other locations including bone, neck lymph node, liver and lung have even been reported in literature [2, 3]. It is widely accepted that the management of CCC of the abdominal wall necessitates wide excision, hysterectomy, bilateral salpingo-oophorectomy with postoperative adjuvant platinum-based chemotherapy. Moreover, not only regional lymph nodes but also the distant metastatic lesion should be concomitantly exercised if a better outcome to be obtained as in this patient. Generally, CCC of the abdominal wall carries a poor prognosis with a median survival time of 30 months as the disease is commonly progressive and can easily recur [2, 3]. More studies are still needed to elucidate the survival benefits of this surgical procedure, the role of adjuvant chemotherapy or radiotherapy, and the protocol of disease follow-up. Article information and declarations Author contributions CYL and FJL contributed to the diagnosis and wrote the manuscript. FLC collected data and photos. JSH reviewed the literature and the manuscript. All authors contributed intellectual content, have read and approved the final manuscript. Funding The authors declare no funding. Acknowledgments None. Conflict of interest The authors declare no competing interests. Supplementary material None.