A lump discovered on the side of the neck often prompts concern, but the vast majority of these masses are benign and relate to a normal bodily function or a minor, temporary issue. The neck contains numerous structures, including lymph nodes, salivary glands, muscles, and soft tissues, all of which can develop swelling or growths. Understanding the potential origins of these masses can provide context, but this information is educational and not a substitute for professional medical advice. A healthcare provider must evaluate any persistent or changing lump to determine its exact cause and ensure appropriate care.
The Body’s Response: Swollen Lymph Nodes
The most frequent cause of a lump on the side of the neck is an enlarged lymph node, a condition known as lymphadenopathy. Lymph nodes are small, bean-shaped structures that are an integral part of the immune system, acting as filters for lymphatic fluid to trap and destroy pathogens. The neck contains approximately 300 of the body’s 600 to 700 lymph nodes, clustered in chains along the sides, back, and under the jawline.
Swelling occurs when the immune cells within the node rapidly multiply to fight an infection or inflammation in the head, neck, or throat area. This reaction is called reactive lymphadenopathy and is a sign that the immune system is actively working. Nodes that are reacting to a common infection, such as a cold or tonsillitis, tend to be soft, mobile, and often tender or painful to the touch.
These reactive nodes usually resolve and return to their normal size within a few weeks after the underlying infection clears. The specific location of the swollen node often indicates the source of the problem; for example, nodes near the jaw may swell due to a dental infection, while those further down the neck often react to throat infections. Persistent or unusually firm lymph node enlargement requires medical follow-up because lymph nodes can also be affected by systemic diseases or certain cancers.
Benign Growths of Skin and Soft Tissue
Lumps can also arise from structural tissues beneath the skin, independent of the immune system. Two common examples are lipomas and cysts, which are non-cancerous growths. Lipomas originate from fat cells and are characterized by a soft, doughy, or rubbery texture, and they are typically movable beneath the skin.
A lipoma is generally slow-growing and painless unless it presses on a nearby nerve or structure. They can appear anywhere on the body but are frequently found on the neck, shoulders, and trunk. Epidermal cysts, often mistakenly called sebaceous cysts, form when skin cells become trapped beneath the surface, creating a sac filled with keratin.
These cysts often feel firmer than a lipoma and may have a small, dark opening called a punctum. They are generally asymptomatic but can become red, swollen, and tender if they rupture or become infected. Removal may be considered if they grow large, cause discomfort, or if the diagnosis needs confirmation.
Causes Related to Glands and Muscle
The side of the neck also houses glands and major muscles that can develop masses. The parotid gland, one of the major salivary glands, is located just in front of the ear and extends toward the jaw angle. Swelling in this gland can feel like a lump on the side of the upper neck or cheek area.
Parotid swelling can be caused by infections, such as mumps, or by blockages within the gland’s ducts, often from small stones that impede the flow of saliva. Swelling related to duct blockage may fluctuate, sometimes becoming more noticeable while eating.
Muscle-related lumps, though less common, involve the sternocleidomastoid (SCM) muscle, which runs diagonally across the side of the neck. Injury or strain can cause a localized muscle knot or hematoma, felt as a firm mass within the muscle tissue. In infants, a condition called torticollis can cause a firm, non-tender mass within the SCM muscle due to trauma during birth or positioning in the womb.
Red Flags and Medical Evaluation
While most neck lumps are benign, a medical evaluation is necessary to rule out less common but more serious conditions. Certain characteristics, often referred to as “red flags,” suggest the need for urgent attention. A lump that is fixed and hard, feeling immobile beneath the skin, or one that is growing rapidly is a cause for concern.
A lump that is painless and persistent for more than two to three weeks, especially in an adult over 40, raises suspicion. Systemic symptoms accompanying the lump are also significant, including unexplained weight loss, night sweats, persistent fever, or difficulty swallowing.
A doctor will begin the evaluation with a detailed history and physical examination, checking the lump’s size, consistency, and mobility. Diagnostics often begin with an ultrasound to visualize the lump’s internal structure, determining if it is solid, cystic, or a cluster of nodes. If malignancy is suspected, the next step is typically a fine-needle aspiration (FNA), a procedure that uses a thin needle to collect cells for laboratory analysis. Imaging techniques like CT or MRI scans may also be used to assess the lump’s relationship to surrounding structures.