Unusual Presentation: Endometrial Stromal Sarcoma Arising in the Colonic Endometriosis

Abstract

Purpose: Endometriosis is a common gynecologic disorder but endometrial malignant transformation is a rare clinical complication. Most common extra-uterine site is ovary. We would like to explore two cases of colonic endometrial carcinomas presenting as colorectal cancer and IBD. Case: Review of two cases of endometrial stromal sarcoma arising in the colonic endometrial implants. First Case: 42 year old female was seen in the clinic due to abdominal pain. Her CT scan showed possible recto sigmoid mass. Colonoscopy confirmed the mass and extensive biopsies were done. Pathology report revealed a well differentiated endometrial stromal sarcoma. There was no evidence of colorectal glandular neoplasia. Markers of GIST, vascular, neural, melanocytic and ovarian stromal tumors are negative. Patient underwent rectosigmoid resection and total abdominal hysterectomy with bilateral salpingo oophorectomy. Results confirmed low grade endometrioid stromal sarcomas from sigmoid colon and multiple extra uterine sites including left ovary. Evidence of sarcoma was not identified in the uterus. Second Case: 64 year old female was seen in the clinic due to rectal bleed. She has a history of hysterectomy with bilateral salpingo oophorectomy 10 years ago for extensive endometriosis. She was diagnosed with ulcerative colitis involving her left colon based on colonoscopy and biopsy results. CT scan showed a thickened sigmoid colon with an adjacent soft tissue mass. She underwent colonoscopy but the scope could not be passed due to a sigmoid colon stricture. She then went to surgery for resection of this portion of the sigmoid colon and adjacent soft tissue mass. Pathology of the surgical specimen showed endometrial carcinoma. Conclusion: Malignant transformation of endometriosis was first reported by Sampson in 1925 (Bullard KM, Am Surg, 2005 Aug; 71(8):694-7). Most common site is ovary with a range from 76 to 79%. Endometrial implants associated intestinal cancers are extremely uncommon clinical condition. Diagnosing these tumors can be some times very challenging. Pathology criteria to support the diagnosis is stromal cell proliferation, positive CD 10 immunohistochemical stains and positive estrogen and progesterone receptors. Abdominal pain and rectal bleeding are common clinical symptoms. We recommend including malignant transformation of endometrial implants as one of the differential diagnosis in women presenting atypically for colorectal cancer or inflammatory bowel disease.Figure: Case 1.