Neuroendocrine cells are a special type that are part of both the nervous and endocrine systems of the body. Neuroendocrine cells are normally found throughout the body.
There are many different types of tumours made up of neuroendocrine cells. The name of the tumour depends on the location in the body and the way the tumour looks when examined under the microscope. Names given to tumours made up of neuroendocrine cells include carcinoid tumour, neuroendocrine tumour, and neuroendocrine carcinoma.
Carcinoid is an old name given to tumours made up of neuroendocrine cells that start in the lung. Although this name is still used, some pathologists now call these tumours neuroendocrine tumours.
Cancers made up of neuroendocrine cells are called neuroendocrine carcinoma. In some areas of the body, neuroendocrine carcinoma is divided into two types based on the size and shape of the cancer cells in the tumour. For example, tumours made up of small cells are called small cell neuroendocrine carcinoma while those made up of large cells are called large cell neuroendocrine carcinoma.
A test called immunohistochemistry can be performed to show that cells are neuroendocrine cells. Pathologists usually look for three proteins called synaptophysin, chromogranin, and CD56 which are made by both normal neuroendocrine cells and neuroendocrine cells in tumours.
Some tumours can start to look like a neuroendocrine tumour even through they are not made up of neuroendocrine cells. Pathologists describe this as neuroendocrine differentiation.
Immunohistochemistry may be performed to show that these cells are producing synaptophysin, chromogranin, or CD56.