Carcinoid apudoma is an illness that manifests in different ways, including physical symptoms and unusual laboratory findings. It usually affects people who have an underlying carcinoid tumor that has spread throughout their liver or lungs. These tumors are neuroendocrine tumors that secrete serotonin and various active peptides that affect other organs’ functions. Furthermore, these tumors can develop anywhere throughout the gut or body. Hence, they can be discovered in the gastrointestinal system and bronchial tree, or airways.
The tumor cells have the ability to expand to the liver and other regions of the body, including the small intestine and appendix, which are the most common sites for carcinoid tumors. At the same time, the lung accounts for 10% of all cases. The rectum, colon, stomach, pancreas, kidney, ovary, prostate, thymus, breast, and other organs are also affected. Moreover, these slow-growing tumors usually spread to the lymph, liver, and nodes, but they can also spread to the bone, lung, brain, and skin.