What is Neuroendocrine Tumour that has affected Irrfan Khan?

Bollywood actor Irrfan Khan on Friday revealed that he has Neuroendocrine Tumour, which can cause abnormal growth in tissues made of hormone-producing nerve cells. The rare condition mostly affects hormones of organs like intestines, lungs, stomach, liver, and not necessarily the brain. The tumour can be cancerous or non-cancerous, and can be treated using surgery, radiation, and chemotherapy.