Salivary gland tumors are abnormal cells growing in the salivary gland or in the tubes (ducts) that drain the glands. Salivary gland tumors can be noncancerous (benign) or cancerous (malignant). Although most salivary gland tumors are benign, some are malignant. Salivary gland tumors are abnormal cells growing in the salivary gland or in the tubes (ducts) that drain the glands. Salivary gland tumors Causes include dehydration, smoking and exposure to radiation. Most salivary tumors are noncancerous, and small blockages may pass without treatment. Severe cases may require the removal of a salivary gland.Salivary gland tumors are growths of abnormal cells (tumors) that begin in the salivary glands. It starts in one of the salivary glands inside or near your mouth.