There are many kinds of neck masses and bumps that can be present in children from birth. Most are just inflammatory and are not cancerous. They can be large or small and often are not noticed until the child gets a cold or sinus infection. Types of more common masses and bumps include:

• Thyroglossal duct cyst. This mass is a small area of fluid or mucus in the neck. It usually goes unnoticed until an infection causes it to swell.
• Branchial cleft cyst. This type of cysts occurs when tissues in the neck and collarbone area do not develop normally, causing spaces of air to form. These can fill with fluid and become infected.
• Dermoid cyst. This is a pocket under the skin that contains tissues normally located in the outer skin layers. The mass may be visible at birth or early infancy, but often is not found until later in childhood.
• Inflammatory Lymphadenitis. Also known as swollen glands, this condition occurs when the glands in the neck become enlarged and inflamed, usually in response to a bacterial or viral infection.
• SCM Tumor of infancy. This is a benign lesion of the cells inside the sternocleidomastoid muscle (SCM). It is the most common neck mass in infants and usually appears between 2 and 4 weeks of age.
• Salivary gland infection. A mass can form when the salivary glands become inflamed and infected. 
• Benign tumors. These masses and bumps are noncancerous growths and do not spread to other parts of the body. 

Rare kinds of neck masses and bumps include:

• Lymphoma, a cancer of the lymph system
• Rhabdomypsarcoma, a cancer of the soft tissues
• Thyroid nodules or thyroid cancer, which forms on the thyroid gland at the base of the neck

Treatments involve treating any infections. Surgery is often recommended to remove a bump or mass if it is impacting function or other nearby tissues or structures.