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What Causes a Hard Back Mass? Your Symptoms Explained

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Last updated February 4, 2021

Hard back mass questionnaire

Use our free symptom checker to find out what's causing your hard back mass.

If you found a hard back mass, it is most likely noncancerous. The most common causes for a hard lump on the back arise from skin conditions, like skin abscess, wart, or cysts on the back. Knots in the back can also appear as a hard back mass. Read below for more information on causes and treatment options.

Hard back mass questionnaire

Use our free symptom checker to find out what's causing your hard back mass.

Hard back mass symptom checker

What is a hard lump on the back?

From balance to posture, the back contains multiple important structures responsible for keeping the body functioning properly. A hard back mass can occur from a variety of causes. If your back mass persists or becomes worrisome, you should see a physician.

Common characteristics of a hard back mass

You may experience the following, directly related to the mass itself.

  • Pain or discomfort: This is especially likely when changing positions or you may have pain that is worse at night.
  • Tenderness to the touch
  • Redness
  • Changes in the appearance of the lump
  • A burning or aching sensation

Common accompanying symptoms

If you have a mass in your back, it's also likely to experience the following.

Less-concerning characteristics

New lumps and bumps in the back can be the initial sign of a cancerous process. However, there are signs and symptoms that can be less worrisome. For example, a lump in the back, even if it is hard, is less concerning if it possesses the following.

  • Easily mobile
  • Reducible: This means it can be pushed back into its place with manual pressure.

More-concerning characteristics

A hard mass in the back will require prompt follow-up if it has the following characteristics.

Your hard back mass may not be directly visible at all times. Sometimes it can be better felt with deep palpation of the area. Therefore, if you experience some of the symptoms above but do not visibly see a mass, you should still see a physician.

What causes a hard lump on the back?

Back structure

A hard mass in the back is usually the result of the growth of underlying structures. There are various structures within the back region, including the following.

  • Nerves: The back is home to the spinal cord, the body’s central support structure and relay center for messages going to and from the body and brain. The nerves in the spinal column provide sensation and allow movement of different parts of the body.
  • Muscles: There are many muscles in the back, both superficial and deep. These muscles allow you to bend, stand, twist, and lift. Extensor muscles help hold the body upright, flexor muscles help you bend, and oblique muscles help you rotate.
  • Fat: There is a layer of fatty tissue under the skin that stores energy, regulates the body’s temperature, and serves as a protective cushion.
  • Lymphatics: The lymphatic system helps rid the body of waste and toxins. It includes a network of tissues and structures in the body and underneath the skin, such as lymph nodes, that allow the body to fight off infections.

Hard back mass questionnaire

Use our free symptom checker to find out what's causing your hard back mass.

Hard back mass symptom checker

Neurologic causes

The spinal cord within the back has nerves protected by a membranous sheath, called the dura, as well as a column of bones, known as the vertebrae. Masses can arise from any of the structures within this system, resulting in a hard mass that may be visible. These masses can either be benign or malignant and require follow-up.

  • Intramedullary: This term can be translated as “in the membrane” and refers to growths from the cells within the spinal cord itself.
  • Extramedullary: This term can be translated as “outside the membrane” and refers to growths from any of the structures outside of the spinal cord, including the nerves that extend from the canal, the bones, and the dura itself.

Skin/Soft tissue causes

Causes related to the skin and soft tissue may include the following.

  • Dermatologic: There are many dermatologic conditions that can result in hard masses in the back. For example, melanoma is a dangerous form of skin cancer that can occur on any part of the body. It may start as a small blemish or point on the skin that can grow, become hard and discolored in the process.
  • Soft tissue: Growths can arise from any of the tissues that support and surround the different parts of the body such as the muscles, fat, tendons and even lining of the joints. Growths that form in this way are known as soft tissue sarcomas and can manifest as hard masses in the back.

Malignant causes

In general, any growth is the result of cells dividing and growing uncontrollably. Sometimes there is a genetic mutation in DNA or a specific protein or failure in an important checkpoint that results in this unchecked growth. These abnormal cells accumulate to form a noticeable lump. A lump can be benign and can arise from many of the causes above; however, if this lump grows and invades the body it is considered malignant. A hard back mass may be the result of a growth in the back itself or cancer spreading from another area. This process is known as metastasis.

Lymphatic causes

The lymph nodes contain immune cells that fight infection and filter harmful substances from the body. When these structures become infected, they can swell and result in palpable lumps. The back contains some lymph nodes that are susceptible to infection and swelling. If swollen lymph nodes are causing the lump in your back, you may also experience tenderness and fever as well.

This list does not constitute medical advice and may not accurately represent what you have.

Skin cyst

A cyst is a small sac or lump, filled with fluid, air, fat, or other material, that begins to grow somewhere in the body for no apparent reason. A skin cyst is one that forms just beneath the skin.

It's believed that skin cysts form around trapped keratin cells – the cells that form the relatively tough outer layer of the skin.

These cysts are not contagious.

Anyone can get a skin cyst, but they are most common in those who are over age 18, have acne, or have injured the skin.

Symptoms include the appearance of a small, rounded lump under the skin. Cysts are normally painless unless infected, when they will be reddened and sore and contain pus.

Diagnosis is made through physical examination. A small cyst can be left alone, though if it is unsightly or large enough to interfere with movement it can be removed in a simple procedure done in a doctor's office. An infected cyst must be treated so that the infection does not spread.

Rarity: Common

Top Symptoms: skin-colored armpit bump, marble sized armpit lump, small armpit lump

Symptoms that always occur with skin cyst: skin-colored armpit bump

Urgency: Wait and watch

Skin abscess

A skin abscess is a large pocket of pus that has formed just beneath the skin. It is caused by bacteria getting under the skin, usually through a small cut or scratch, and beginning to multiply. The body fights the invasion with white blood cells, which kill some of the infected tissue but form pus within the cavity that remains.

Symptoms include a large, red, swollen, painful lump of pus anywhere on the body beneath the skin. There may be fever, chills, and body aches from the infection.

If not treated, there is the risk of an abscess enlarging, spreading, and causing serious illness.

Diagnosis is made through physical examination.

A small abscess may heal on its own, through the body's immune system. But some will need to be drained or lanced in a medical provider's office so that the pus can be cleaned out. Antibiotics are usually prescribed.

Keeping the skin clean, and using only clean clothes and towels, will help to make sure that the abscess does not recur.

Rarity: Common

Top Symptoms: rash with bumps or blisters, red rash, red skin bump larger than 1/2 cm in diameter, pus-filled rash, rash

Symptoms that always occur with skin abscess: rash with bumps or blisters

Urgency: Primary care doctor

Basal cell carcinoma

Basal cell carcinoma is a slow-growing form of skin cancer. Skin cancer falls into two major groups: Non-melanoma and melanoma. Basal cell carcinoma is a type of non-melanoma skin cancer.

Rarity: Uncommon

Top Symptoms: facial skin changes, pink or red facial bump, small facial lump, painless facial bump, growing facial lump

Urgency: Primary care doctor


Warts, also called common warts or verrucae, are small, rough, rounded growths on the top layer of the skin. They may appear alone or in clusters. Common warts are caused by the human papillomavirus (HPV) and are contagious through direct contact. They may spread from one place on the body to another simply through touch.


Hard back mass questionnaire

Use our free symptom checker to find out what's causing your hard back mass.

Hard back mass symptom checker

How and when to treat a hard lump on the back

Since the causes of hard back masses are varied, it is important to see your physician for a proper diagnosis and treatment plan. Depending on the cause of your symptoms, your physician may suggest the following.

  • Surgery: Surgery is often the first-line option for removing both benign and malignant growths from the back and other areas of the body.
  • Antibiotics: If you have swollen lymph nodes due to infection, your physician will provide appropriate antibiotic treatment.
  • Cancer treatment: If your hard back mass and associated symptoms are due to cancer, your physician will discuss treatment options including surgery, radiation, or chemotherapy.

FAQs about hard back mass

Can I lay down on a hard back mass?

Hard back masses are often uncomfortable and make activities such as lying down very difficult. If you can tolerate lying directly on your back, it is okay to do so.

Will a hard back mass affect how I walk?

Depending on the cause and location of your hard back mass, your gait may be affected. For example, if your hard back mass is a growth of the spinal cord/column, nerves that assist in walking may be damaged or compressed. If you experience clumsiness, trouble walking, fatigue, or unexplained weight loss, make an appointment with your physician promptly.

Can I still exercise with a hard back mass?

Exercise is acceptable if you do not aggravate the area of the mass. Low-intensity or low-impact exercises such as dancing, walking, or water aerobics may be good options. However, activities such as heavy weightlifting can cause strain or further inflammation. Always speak with your physician before beginning an exercise regimen.

Will the hard mass on my back grow larger?

Depending on the cause of your symptoms, a hard back mass may grow in size. In the cases of cancerous growths such as melanoma or soft tissue sarcoma, growth and spread are possible.

Can a hard back mass be inherited?

Some back masses related to cancerous processes can be inherited. For example, the mutation that causes some forms of soft tissue sarcoma can be inherited. However, infections affecting the lymphatic system are usually not inherited.

Questions your doctor may ask about hard back mass

  • What color is the bump?
  • Do you purposely tan (using sun, tanning beds, or UV rays)?
  • Do you feel pain when you touch the bump?
  • Has anyone in your family had cancer?

Self-diagnose with our free Buoy Assistant if you answer yes on any of these questions.

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Dr. Rothschild has been a faculty member at Brigham and Women’s Hospital where he is an Associate Professor of Medicine at Harvard Medical School. He currently practices as a hospitalist at Newton Wellesley Hospital. In 1978, Dr. Rothschild received his MD at the Medical College of Wisconsin and trained in internal medicine followed by a fellowship in critical care medicine. He also received an MP...
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  1. Back muscles. Cedars-Sinai. Cedars-Sinai Link
  2. Swollen lymph nodes. University of Michigan: Michigan Medicine. Reviewed July 30, 2018. U of M Health Link
  3. Spinal tumors. American Association of Neurological Surgeons. AANS Link
  4. Soft tissue masses. University of Washington Medicine: Orthopaedics and Sports Medicine. UW Medicine Link
  5. Signs and symptoms of soft tissue sarcomas. American Cancer Society. Updated April 6, 2018. American Cancer Society Link