Tumors of the appendix: II. The spectrum of carcinoid.

We reviewed the clinical data and pathologic material from 30 patients with appendiceal carcinoids. Most of the tumors were discovered incidentally in appendectomy specimens. Approximately two thirds were tiny lesions identified only by microscopic examination. One tumor metastasized to a regional lymph node. Five histologic patterns were identified. Problems in differential diagnosis may arise in interpreting the variant patterns, but these patterns appear to have no bearing on prognosis. In reviewing the literature we found that appendiceal carcinoids infrequently metastasize widely and only rarely produce the carcinoid syndrome.