Association between mucosal hyperplasia of the appendix and adenocarcinoma of the colon.

Mucosal hyperplasia of the appendix is a seemingly benign change of poorly understood significance, at times found in patients with colorectal malignancy. To determine the incidence of this change and its association with colonic adenocarcinoma, we have examined the appendiceal mucosa in 122 ileocolectomy specimens gathered between 1987 and 1990, and in 273 consecutive appendectomies carried out during 1990 at The Methodist Hospital in Houston, Texas. We found that 23 out of 122 ileocolectomies (18.8%) showed mucosal hyperplasia of the appendix and, of these, 17 (77%) were associated with colorectal malignancy, predominantly of the right side. Moreover, 24 of 273 appendectomies (8.8%) exhibited the presence of mucosal hyperplasia and, of these, six (25%) also were associated with adenocarcinoma of the colon. On the basis of this significant rate of association, we feel that a concomitant colorectal carcinoma should be ruled out in patients who exhibit mucosal hyperplasia of the appendix.