Clear cell carcinoma originating in the abdominal wall is rare and usually develops within endometriotic implants in the scar. We describe 2 patients: a 42 year old with a 15 cm mass on the abdominal wall treated with neoadjuvant chemotherapy and excision and a 51 year old with a 6 cm abdominal mass treated with excision and adjuvant radiotherapy.
Endometriosis developing in a cesarean section or hysterectomy scar is an unusual event. Reports of malignant transformation originating on the background of scar endometriosis in the abdominal wall are extremely rare. We present 2 cases with abdominal wall clear cell carcinoma on a background of endometriosis.
Case Report 1
A 42 year old G5P3 presented with a 15 cm, soft tissue mass in the anterior abdominal wall inferior to the umbilicus. Her past surgical and obstetric histories were significant for 2 cesarean sections, tubal ligation, and right oophorectomy secondary to an ovarian cyst with benign pathology. Her β-human chorionic gonadotropin (HCG) was 63 mIU/mL. An abdominal ultrasound revealed multiple fibroids with no intra- or extrauterine pregnancy. The abdominal computed tomography (CT) scan was consistent with a 16.3 × 14.3 × 17.8 cm mass in the lower abdominal wall ( Figures 1 and 2 ). Her CA-19-9 was 45 U/mL but CA 125, α-fetoprotein, and carcinoembryonic antigen were all normal.
A biopsy of the abdominal mass revealed tumor cells possibly of mullerian origin. Her Papanicolaou smear and CT scan of the thorax were normal. Because of the size of the tumor, which was deemed to be unresectable, a decision was made to proceed with neoadjuvant chemotherapy consisting of paclitaxel and carboplatin every 21 days. After the eighth cycle of chemotherapy, the tumor decreased in size to 11.4 × 8.2 cm ( Figure 3 ) and the β-HCG decreased to 6 mIU/mL. A positron emission tomography (PET) scan showed no focal increased 18 F-fluorodeoxyglucose uptake above the diaphragm.
A multidisciplinary approach was followed for this patient’s treatment, which involves medical oncology, surgical oncology, gynecologic oncology, and plastic surgery. At laparotomy, radical resection of the abdominal wall mass ( Figure 4 ), partial omentectomy, total abdominal hysterectomy, right salpingo-oophorectomy, left pelvic lymphadenectomy, and abdominal wall reconstruction were performed. The patient was discharged on postoperative day 8 and was still in recovery process 1 month after surgery at the time of this manuscript preparation.
Pathologic examination showed a primary clear cell carcinoma of the abdominal wall, possibly arising in an endometriotic implant. The carcinoma appeared to be confined to the abdominal wall with margins free of disease. All other organs and lymph nodes showed no evidence of malignancy.
Case Report 2
A 51 year old G6P6 patient presented with a 6 cm right lower quadrant abdominal wall mass of 1 year’s duration. The patient’s past medical history was significant for hypertension and deep venous thrombosis, and past surgeries included 2 cesarean section and hysterectomy for uterine fibroids in 1994. Her family history was significant for an aunt with uterine cancer and 2 cousins with breast cancer.
The CT of the abdomen revealed a right lower quadrant abdominal wall mass measuring 7 × 5 × 3 cm ( Figure 5 ). An excisional biopsy was performed and pathologic examination showed clear cell adenocarcinoma arising from a focus of extraovarian endometriosis with clear margins. Two months after her initial surgery, the patient underwent a laparoscopic bilateral salphingo-oophorectomy and an omental biopsy, and the pathologic examination was without any malignancy. A PET scan was performed, which was without evidence of metastasis. The patient had adjuvant radiotherapy consisting of 50.4 Gy to the right side of the abdomen and still alive without any evidence of disease at 31 months of follow-up.
