Which of the following statement about carcinoid of appendix is NOT TRUE?

Remember these points about carcinoid tumour of appendix Carcinoid tumors are neuroendocrine tumors arising in the argentaffin tissue (kulchitsky cells of crypts of lieberkuhn) They frequently contain sustentacular cells that express S -100 These tumors occur in any pa of the appendix but most common site is distal third i.e. tip of appendix Unlike carcinoid tumors arising in other pa of the GIT it rarely gives rise to metastasis. Ref: Sabiston 18/e, Page 1345; Schwaz 9/e, Page 1088; Bailey & Love 25/e, Page 1217.