Carcinoid tumourlet

by Jason Wasserman MD PhD FRCPC
March 7, 2023


What is a carcinoid tumourlet?

A carcinoid tumourlet is a group of neuroendocrine cells in the lung that measures less than 5 millimeters in size. In addition to the size, a group of neuroendocrine cells can only be called a tumourlet if the cells do not show any abnormal features such as an increased number of mitotic figures (cells dividing to create new cells) or a type of cell death called necrosis.

Is a carcinoid tumourlet a type of cancer?

Most pathologists consider carcinoid tumourlets to be a non-cancerous overgrowth of neuroendocrine cells and not a type of cancer. Neuroendocrine cells are specialized cells that are normally found in the walls of the airways throughout the lungs. Carcinoid tumourlets are often found incidentally when lung tissue is removed for another reason.

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Typical carcinoid tumour

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