Light micrograph of a section of a human salivary gland tissue showing evidence of salivary gland cancer. This is a rare disease in which malignant (cancerous) cells form in the tissues of the salivary glands. It is classed as a head and neck cancer with the usual signs being a lump in the area of the ear, cheek, jaw, lip or inside the mouth. Trouble in swallowing is another feature of the disease. The cancer may not show any obvious symptoms, but may be found during a regular dental check up or physical examination. Many salivary gland cancers can often be cured, especially if found early.