Carcinoid is found coincidentally in approximately 1 of every 200 appendixes removed. Its importance depends on its size and also whether its growth is limited to just the lining of the appendix. Most of them are tiny and just a harmless curiosity. Those few which are larger or have invaded into or through the wall of the appendix require a second, more extensive, operation to thoroughly clean out the area to which the appendix was attached. These few patients will require periodic X-ray and blood tests in the future years to watch for recurrence or spread.
Carcinoid syndrome almost never comes from appendiceal carcinoids and the 1 or 2 cases reported required extensive and obvious metastases to cause the syndrome. Usually carcinoids of the appendix are coincidental findings and have not spread until greater than 2 cm in diameter. However, even with a small one (under 2 cm) it is important to know that the tumor has not gone through the full thickness of the appendix wall and does not show any microscopic invasion of lymph nodes and blood vessels. If all these criteria are okay, then you are cured and no further testing is required.