Atypical sigmoid metastasis from a high-grade mixed adenocarcinoma of the ovary

Background. Intraperitoneal seeding is the most common form of dissemination of epithelial ovarian cancer. Metastasis to the bowel mucosa can occur by invasion from the serosal surface or infiltration of the submucosal capillary network. Hematogenous dissemination usually occurs in the presence of advanced peritoneal disease. Case. A 39-year-old gravida 3 para 2 woman was diagnosed in October 2000 with a large pelvic mass. She underwent an exploratory laparotomy and a left salpingo-oophorectomy with multiple abdominal and pelvic biopsies. She was diagnosed with an ovarian tumor of low malignant potential, and no further treatment was recommended. Six months later, she developed abdominal discomfort and constipation. A colonoscopy was performed, and a biopsy showed metastatic carcinoma of ovarian origin. The patient presented to The University of Texas M.D. Anderson Cancer Center in September 2001 for consultation. The surgical pathology evaluation from her previous surgery indicated high-grade ovarian carcinoma. The patient underwent a total abdominal hysterectomy, right salpingo-oophorectomy, infracolic omentectomy, right pelvic lymph node sampling, and segmental resection with primary end-to-end sigmoid colon anastomosis. The tumor within the colon was a polypoid mass arising from the mucosa with no involvement of the colonic wall. Microscopically, the tumor was a high-grade ovarian papillary serous carcinoma with areas of endometrioid adenocarcinoma. The colonic tumor was immunohistochemically positive for cytokeratin-7 and negative for cytokeratin-20. The patient was treated with six cycles of carboplatin and paclitaxel. The patient then incidentally developed disseminated sarcoidosis. At the time of this report, the patient had no evidence of recurrent or metastatic disease for 2 years. Conclusions. Epithelial ovarian carcinomas may recur as intraluminal bowel lesions with serosal sparing even in the absence of peritoneal disease. Immunohistochemical staining using cytokeratins-7 and -20 may prove useful in differentiating such lesions from primary colonic malignancies.