Lump on Neck or Back of Neck: Information to Know

Written by: Dana-Farber Editorial Team
Medically Reviewed By: Kartik Sehgal, MD

Key Takeaways:

  • Most lumps are not a sign of cancer. However, if you have a lump on your neck that isn’t going away it should be examined by a doctor.
  • A cancerous lump can vary in size and location, and some people may even feel a cluster of lumps grouped together.

The first thing you should know is that most neck lumps are not a sign of cancer. There are a host of more common causes of neck lumps, including infections, cysts, boils, and other common skin irritations.

However, a neck lump can also be an early sign of several types of cancer, so if your lump does not go away in a week or two, you should consult with your doctor. If your neck lump is caused by a swollen lymph node, it could be cancerous — but again, this is far from the most likely explanation.

What are the lymph nodes and how are they related to neck lumps?

Lymph nodes are key components of the body’s immune system. These small, bean-shaped capsules are located throughout the body and are responsible for filtering and removing harmful substances from your body. Hundreds of lymph nodes are connected by a vascular system that transports white blood cells, which help fight infections by attacking germs, bacteria, and diseases. This is similar to the system that transports blood.

The most common cause of swollen lymph nodes is that they are fighting an infection, which indicates that they are operating effectively as part of your immune system. If this is the cause, the swelling will disappear as soon as the infection is defeated.

Can a neck lump or swollen lymph nodes be a sign of cancer?

In rare cases, swollen lymph nodes can be the first sign of cancer. Unlike a lump caused by infection, a cancerous lump will rarely disappear. Therefore, if the lump persists for more than a week or so, you should consult your doctor. (Other significant ailments can cause the lymph nodes to swell, including strep throat, mononucleosis, tonsilitis, and HIV.)

“Feeling a lump in your neck is not a reason to panic,” says Kartik Sehgal, MD, a head and neck medical oncologist and director of the Thyroid Cancer Center at Dana-Farber Brigham Cancer Center. “While the majority of lumps are benign, it’s important to report persistent lumps and associated symptoms to your doctor.”

What does a cancerous neck lump feel like?

Cancerous lymph nodes can occur anywhere on the neck and are typically described as hard rather than squishy like the swollen nodes caused by infection. The lumps can range in size from a half-inch to several inches in diameter.

While you may only notice a single lump, it is not uncommon to find them clumped together, spread out along one side of the neck, or even along both sides of the neck depending on the location of a possible tumor. Although they are usually painless, some cancerous lymph nodes can become painful after drinking alcohol.

In the case of cancer, the lump occurs when cancer cells infiltrate the lymph capsule and multiply rapidly. If left untreated, cancer can break out of the lymph node and spread to other parts of the body.

What types of cancer might a neck lump indicate?

A neck lump is often the only symptom of head and neck cancer, which is why it’s important to monitor lumps and consult your doctor if they don’t go away. The types of cancer that are most frequently associated with neck lumps are:

  • Lymphoma, which falls into two broad categories, Hodgkin lymphoma and non-Hodgkin lymphoma. Both are cancers of the lymphatic system which fight infection and disease. A swollen lymph node is the most common, and often the earliest, symptom of lymphoma.
  • Leukemia is a general term for blood cancer. Leukemia generally begins in the bone marrow and can often result in swollen lymph nodes.
  • Thyroid cancer occurs in the butterfly-shaped gland at the front base of your neck. This gland produces hormones to regulate heart rate, blood pressure, and weight. A lump caused by thyroid cancer will most likely be located at the front of your neck below the voice box. While 80 to 90 percent of reported thyroid lumps are not cancerous, it’s important to inform your healthcare provider if you notice any changes.
  • Any metastasized cancer that has spread beyond its place of origin and entered the lymphatic system.

How is a cancerous lymph node diagnosed?

If your lymph node has been swollen for several weeks, a biopsy may be required to determine if it is cancerous. The biopsy may be done by surgically removing the node, or by inserting a needle to take a smaller sample. If cancer is found, doctors may use various imaging technologies (X-ray, CT scan, PET scan, or MRI) to determine if the cancer originated in the lymph node or metastasized from another part of your body.

Other than cancer, what can cause a neck lump?

In addition to swollen lymph nodes, there are a variety of ailments that can cause lumps beneath the skin of the neck and aren’t usually related to cancer, including:

  • Thyroid nodules are lumps that live under the skin in the front of the neck. They can either be fluid-filled or solid and are usually harmless. In rare cases, thyroid lumps can prove to be cancerous.
  • An infection below the surface of the skin.
  • A cyst, which is a slow-growing bump under the skin, has a smooth surface and is usually painless. Cysts are usually not cause for concern unless they become infected or grow very large. Sometimes cysts can emit a thick, yellow, smelly fluid.
  • Boils are typically caused by a bacterial or fungal infection due to a blocked hair follicle or oil gland. Although they can appear anywhere, they are often found on the neck. Boils are red and painful lumps with a yellow or white center. They are caused by a localized infection that rarely spreads beyond the boil itself. They may rupture and weep fluid. You should not squeeze or prick a boil since this can cause the infection to become worse or spread. Instead, apply warm compresses and keep the area clean.  
  • An allergic reaction to many substances can irritate the neck, including detergent residue, shampoo, and sunscreen. Lumps caused by an allergic reaction are often itchy or painful.
  • Muscle knots, including on the back of the neck, from injury, overuse, or tension. These knots can be as small as a pea or as large as a baseball. They are typically invisible since they remain beneath the skin and don’t cause lumps. It will often be painful to push on a muscle knot, whereas a cancerous lymph node is rarely painful.
  • Lipoma is a fatty tissue deposit that is not painful and is unlikely to cause other problems.
  • Mononucleosis is caused by infection with a contagious virus that can last months. It can cause swollen lymph nodes in addition to the more widely known symptoms such as extreme fatigue, fever, sore throat, and headaches.

About the Medical Reviewer

Kartik Sehgal, MD

Dr. Sehgal completed his fellowship training in hematology and medical oncology at Beth Israel Deaconess Medical Center, a Harvard Medical School teaching hospital, in 2020. Prior to this, he earned his medical degree from the All India Institute of Medical Sciences, New Delhi, and finished residency training in internal medicine at Yale-New Haven Hospital, CT. Dr. Sehgal's research interests are in the fields of translational immuno-oncology and experimental therapeutics. He has previously trained in the Dhodapkar Laboratory at Yale University and Barbie Laboratory at Dana-Farber Cancer Institute. His research has led to publications in scientific journals such as Science Translational Medicine, Nature Medicine, Blood and Journal of Immunology. He is currently engaged in clinical and translational research directed towards delineating mechanisms of therapeutic resistance to immune checkpoint inhibitors and developing more effective combinations with molecularly targeted therapies.