Source:http://linkedlifedata.com/resource/umls/id/C0024897
NCI: A growth or lump of mast cells (a type of white blood cell). Mast cell tumors can involve the skin, subcutaneous tissue, and muscle tissue.,NCI: A localized tumor composed of sheets of mast cells without atypia. It includes the cutaneous mastocytoma which involves the dermis and subcutaneous tissue, and the extracutaneous mastocytoma. Most cases of extracutaneous mastocytoma have been reported in the lung.