Case Provided by John Laverty, MD

Case History

The patient is an 80 year old female with gastrointestinal bleeding, hemo cult positive stool and iron deficiency anemia. At colonoscopy, a primary colorectal neoplasm 12 cm from the anal verge was identified. A subsequent low anterior resection was performed with removal of the large ovary.

Microscopic Findings

Sections from the colonic lesion showed a moderately differentiated adenocarcinoma. The ovarian tumor showed similar histological features; however, rare focal papillary pattern was discovered.  Immunohistochemical stains were performed with the following results: the colonic adenocarcinoma was positive for monoclonal and polyclonal CEA, CK20 and CDX-2 and negative for CK7.  The ovarian neoplasm showed positivity for CK7, CA-125, and weak positivity with progesterone receptor.  Monoclonal CEA and CK20 stains were negative.




Metastatic ovarian carcinoma must be distinguished from primary ovarian carcinomas because of their dramatically different treatments and outcomes.  Features that favor a metastatic tumor are: bilaterality, surface involvement, stromal invasion, nodular invasive pattern, hilar involvement, single cell invasion and signet ring cells. Features that favor primary carcinoma are: expansive invasion, complex papillary pattern, large size> 10 cm, smooth external surface, and benign and borderline appearing areas. The following immunostains may aid in distinguishing primary from metastatic tumors: CK7, CK20, MUC2, CDX-2 and B-Catenin.  Primary mucinous ovarian tumors are: CK7+, CK20-, CDX-2-, MUC2-, and B-Catenin -. Metastatic carcinomas from colon and appendix are:CK7-, CK20+, CDX-2+, MUC2+ and B-Catenin+.  It should be noted that tumors of the upper GI tract and hepatobilliary tree are often CK7+. 


  1. Cathro HP, Stoler MH:  Expression of cytokeratins 7 and 20 in ovarian neoplasia. American Journal of Clinical Pathology 2002; 117(6): 944-51.
  2. Lewis, MR, Deavers MT, Silva EG, Malpica A.  Ovarian Involvement by Metastatic Colorectal Adenocarcinoma.  American Journal of Surgical Pathology 2006; 30(2): 177-184.
  3. O’Connell JT, Hacker CM, Barsky SH.  MUC2 is a molecular marker for psedomyxoma Peritonei, Modern Pathology 2002; 15 (9): 958-72.




Low Power Magnification: malignant glands invading muscularis propria (rectosigmoid tumor)
High Power Magnification: inflammatory background (rectosigmoid tumor)
CEA monoclonal rectosigmoid tumor
Cytokeratin (CK20) rectosigmoid tumor
CDX-2 rectosigmoid tumor
Left Ovary; Low Power Magnification: malignant glands forming expansive infiltrative tumor. Note small focus with papillary pattern at the lower right corner
Left Ovary: malignant glands in inflammatory background
CA-125, Left Ovary
Cytokeratin 7 (CK7), Left Ovary