Two cases of colorectal cancer in which ascitic examination by the cell block technique was useful for differentiation from ovarian cancer

Background : In women with a pelvic mass and massive ascites, gynecologic cancer, such as ovarian cancer, is often suspected. When ascitic fluid cytology reveals adenocarcinoma cells, it is sometimes difficult on the basis of cytology alone to diagnose the primary cancer site. Two patients with massive ascites were referred to the gynecology department by physician. Colorectal cancer was suspected from the results of ascitic fluid examination by the cell block technique, and lower gastrointestinal endoscopy led to the diagnosis of advanced colorectal cancer.Cases : Case 1 : A 71-year-old woman was admitted to our hospital because of abdominal distention. She had ascites and other evidence of peritoneal dissemination, and was suspected as having ovarian cancer. Ascitic fluid cytology revealed evidence of adenocarcinoma. Immunohistochemical examination of cell blocks prepared from the cytology specimens revealed positive staining of the tumor cells for CDX2 and CK20. Lower gastrointestinal endoscopy led to the diagnosis of appendiceal cancer. Case 2 : A 72-year-old woman was presented with abdominal distension was suspected as having ovarian cancer with peritoneal dissemination. Ascitic fluid cytology revealed adenocarcinoma cells. Immunohistochemical examination of cell block specimens prepared from the cytology specimens revealed positive staining for CDX2 and CK20. Lower gastrointestinal endoscopy led to the diagnosis of cecal cancer.Conclusion : In patients with peritonitis carcinomatosa, it is very useful to use the cell block technique in combination with ascitic fluid cytology to diagnose the primary cancer site.