High-grade endometrial stromal sarcoma arising from colon endometriosis

Abstract

Dear Editor, Malignant transformation is a rare but well-documented complication of endometriosis, occurring only 0.7 to 1% of the cases. Among these cases, nearly 76% arose in the ovary, and colorectal involvement was only 5%. Most of these malignant neoplasms are endometrial adenocarcinoma. Yantiss et al. reported only one endometrial stromal sarcoma (ESS) identified among 17 malignant neoplasms arising in gastrointestinal endometriosis. Experience of treatment with this tumor is limited due to their rare occurrence. We present a case of high-grade ESS of the sigmoid colon arising in extrauterine endometriosis managed by complete surgical excision and adjuvant radiotherapy. A 42-year-old woman presented with a 1-month history of difficult defecation and rectal bleeding. The bleeding was bright red in color, occurred at irregular intervals, and was associated with bowel movements. She had a 5-year history of non-small-cell lung cancer, undergoing chemotherapy at an outpatient department. She was multipara and had no history of endometriosis or taking hormonal drugs. The physical examination did not show an abdominal tenderness or a palpable mass. The digital rectal examination did not reveal any mass or blood. The results of the laboratory tests were unremarkable. Barium enema showed an apple-core-filling defect with mucosal destruction at the sigmoid colon. The computed tomography (CT) of the abdomen revealed a segmental wall thickening of the rectosigmoid junction with adjacent mesocolon soft tissue nodules, which was considered as an adenocarcinoma of the sigmoid colon with regional lymph nodes metastasis. The subsequent colonoscopy found a polypoid mass in the sigmoid colon with a narrowing of the bowel lumen. The biopsy results showed endometriosis characterized by pictures of the stromal cell’s hyperplasia with uniform, round to spindle nuclei, and focal lymphocytic infiltration, and positive immunohistochemical stains for CD10, estrogen receptor, and progesterone receptor. The surgical intervention arranged was due to the symptoms of stenosis of the rectosigmoid colon. At laparotomy, multiple red and brown cystic-like masses over the omentum, sigmoid colon, and left ovary were found. The frozen sections showed ESS arising from endometriosis. The surgical procedures included rectosigmoidectomy, total hysterectomy, bilateral salpingo-oophorectomy, and partial omentectomy. Grossly, the resected sigmoid colon had multiple 1to 3-cm nodular masses involving areas from the mucosa to the pericolic fatty tissue. Histologically, the sections of the rectosigmoid colon showed high-grade ESS characterized by multiple foci of tumor cell nests with crowded hyperchromatic nuclei extending from the colon mucosa to the pericolic fatty tissue. The tumor showed frequent mitosis, accounting more than ten mitotic figures per 10 high power fields (MF/10 HPF), and increased the proliferating index to approximately 12%. There were multiple foci of tumor necrosis and lymphovascular identification. The tumor cells were immunohistochemically positive for vimentin, MIB-1 (Ki-67), estrogen receptor (ER), progesterone receptor (PR), and CD10, but negative for cytokeratin, smooth muscle actin, and Int J Colorectal Dis (2007) 22:1551–1553 DOI 10.1007/s00384-006-0267-6