A sarcoma is a tumor made of cells from connective tissue.

Mast cell sarcoma is an extremely rare tumor.

People with a mast cell sarcoma have no skin lesions, and pathology examination of the tumor shows it to be very malignant with an aggressive growth pattern.

[4] Mast cell sarcoma should not be confused with extracutaneous mastocytoma, a rare benign mast cell tumor without destructive growth.

In the cases observed, mast cell sarcoma terminated quickly as mast cell leukemia; one of the most aggressive human cancers.