Combined goblet cell carcinoid and mucinous cystadenoma of the appendix.

Two cases of combined goblet cell carcinoid and mucinous cystadenoma occurring in the appendix are reported. The histogenesis of the goblet cell carcinoid remains one of its most controversial aspects and the occurrence of both of these relatively uncommon tumours in the same organ may lend support to the unitary stem cell hypothesis on the origin of this tumour. Alternatively, this occurrence may represent an example of the adenoma/carcinoma sequence.