It is the job of glands within the neuroendocrine system to produce hormones (chemicals that our bodies need) to travel in our blood stream. When a tumour occurs in these glands, it is called a carcinoid or carcinoid tumour. Islet cells are found within our pancreas, which is part of our digestive system. An Islet cell carcinoma therefore is a tumour of islet cells in the pancreas. There are two types of carcinoid tumour, typical and atypical. A typical tumour grows slowly whilst an atypical tumour grows at a faster rate.