Goblet cell carcinoid of the appendix: Investigation of the expression of beta-catenin and E-cadherin

Goblet cell carcinoids are rare neoplasms that predominantly occur in the a ppendix. In this report we present a case of goblet cell carcinoid of the a ppendix. A 58-year-old male patient complaining of pain in the right lower quadrant was diagnosed with acute appendicitis and underwent an appendectom y. Histological examination of the resected appendix revealed goblet cell c arcinoid. Infiltration of tumor cells beyond the appendix was observed and the surgically resected margin was positive for tumor cells. Carcinoembryon ic antigen (CEA) was diffusely detected by immunohistochemistry, and cytoke ratin 20, neuron-specific enolase (NSE), chromogranin A and serotonin were focally observed in the tumor cells. The expression of beta -catenin and E- cadherin was investigated to compare with that of typical rectal carcinoids (n = 3) and colon adenocarcinomas (n = 3). In normal colonic and rectal mu cosae, beta -catenin and E-cadherin stained positive on the plasma membrane . In the case reported here, beta -catenin showed a preserved expression on the plasma membrane of goblet cell carcinoid; a pattern similar to typical carcinoids rather than to adenocarcinomas, However, E-cadherin demonstrate d a reduced expression on the plasma membrane of the tumor cells. This stai ning pattern was identical to those both of carcinoids and of adenocarcinom as, These findings suggest the possibility that, in some cases, the adheren s junctions of goblet cell carcinoids are similar to those of typical carci noids rather than to those of adenocarcinomas.