Granular cell tumour is a non-cancerous type of tumour made up of large pink granular cells. The tumour is believed to originate from cells normally found in neural tissue such as a nerve. Granular cell tumours can develop anywhere in the body although they are most commonly found inside the mouth, breast, or skin. In only rare cases will the tumour behave like a cancer by spreading to other parts of the body.
The diagnosis of granular cell tumour is usually made after the entire tumour has been surgically removed and sent to a pathologist for examination under the microscope. For large tumours, your doctor may first remove a small tissue sample in a procedure called a biopsy.
When examined under the microscope, the tumour is made up of large pink cells. The cells appear pink because the body of the cell is full of round material called granules. A test called immunohistochemistry is sometimes performed to confirm the diagnosis. When performed, the tumour cells are positive or reactive for the S100, SOX-10, and CD68 and are negative for cytokeratins.