When to Worry vs. Not Worry About Lumps Under Your Skin

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If you’ve found a lump or bump under your skin, you might worry that it’s something serious. The good news is most lumps are harmless. Still, you should see a healthcare provider any time you notice an unexplained growth or unusual swelling. 

Bumps can crop up in all different places on your body. They can be benign (noncancerous), malignant (cancerous), or infectious (caused by an infection). Normal, benign lumps typically feel soft and roll easily under your fingers. They may cause pain if they become infected or inflamed. On the other hand, cancerous lumps usually grow in size and are hard, large, and painless.

This article will discuss the most common types of skin lumps and when you should worry about a potentially dangerous lesion.

A close-up of a woman feeling under her armpit

triocean / Getty Images

13 Possible Types of Lumps Under Skin

There are many types of skin lumps, and they can have different causes.


A cyst is a sac that may contain fluid, air, tissue, or another material. It can form when normal skin cellular turnover is disturbed. Most of the time, cysts are not cancerous.

You can spot a cyst by looking for a small opening, called a pore or punctum, in the center of the lump. But sometimes, this pore is hard to see. Cysts typically have a smooth surface and roll under the skin when pressure is applied.

There are hundreds of different types of cysts. Some common ones are:

  • Epidermoid cysts: These contain skin cells and protein.
  • Sebaceous cysts: These are small sacs that are filled with keratin (a fibrous protein found in hair, nails, and skin).
  • Ganglion cysts: These appear on top of a joint or tendon and are caused by an accumulation of leaking joint fluid.
  • Baker’s cysts: These are caused by a buildup of trapped joint fluid behind the knee.
  • Breast or ovarian cysts: These are usually benign.


Lipomas are benign growths that are made up of fat tissue. They’re soft, small, and rubbery lumps that sit just below the skin. Most lipomas appear on the shoulders, upper back, arms, buttocks, and upper thighs.

They typically don't cause pain and may move if you push on them gently. Lipomas don’t require treatment unless they cause discomfort or are unsightly.

Cause of Lipomas

The exact cause of lipomas isn't known, but some research shows genetics may play a role.


A dermatofibroma is a small, round, noncancerous bump. They’re usually pink, reddish, or brown. Typically, dermatofibromas can be left alone, but surgery is an option for some people. 

Swollen Lymph Nodes

If a lymph node is swollen, it can cause what looks like a bump under the skin. These lumps may be painful and feel hard.

Lymph nodes are bean-shaped organs in the lymphatic system. They house immune cells and serve to filter foreign particles from body fluids. They can enlarge and swell as part of the body’s response to a bacterial or viral infection. Less commonly, lymph node swelling can be a sign of cancer or another serious condition.

You may be able to feel lymph nodes in certain areas of your body, including the following:

  • Groin
  • Armpit
  • Neck
  • Under the chin and jaw
  • Back of the head
  • Behind the ears


Moles are common skin growths that develop when skin cells grow in a cluster. Most adults have 20 to 40 moles. They range in color from flesh-toned to dark brown. Moles are usually harmless, but some can be cancerous. It’s a good idea to have a healthcare provider look at any suspicious mole.


Warts are noncancerous growths on the skin that are caused by the human papillomavirus (HPV). They can grow anywhere but commonly crop up on the hands, fingers, and feet. There are different types of warts, including:

  • Common warts: These are usually small, hard bumps that are dome-shaped and grayish-brown in color. They have a rough surface that might resemble a cauliflower, with black dots.
  • Flat warts: These warts are smoother and have flat tops. They can be pink, light brown, or yellow.
  • Plantar warts: These usually form on the bottom of the foot and can be painful.
  • Filiform warts: These are shaped like a finger and are usually flesh-colored.

Boils and Abscesses

Boils and abscesses are hard, painful lumps filled with pus (a collection of white blood cells, microbes, and tissue debris). They’re typically caused by bacteria.

A boil is more superficial and can appear anywhere on the body but commonly affects the neck, face, armpits, buttocks, and thighs. An abscess may be deeper and the skin over it appear red, raised, and swollen.

You might also be able to see yellow or white in the lump due to the pus that’s underneath the surface of your skin. Some people also experience fever and chills with an abscess.

Often, a boil or abscess will break and drain on its own. But sometimes a healthcare provider must intervene and drain the pus.

Hands Off

You shouldn't try to pick or pop a boil, abscess, or other lump. This can lead to an infection or cause the lump to grow in size.


A hernia occurs when a body part bulges through the wall of muscle or tissue that normally holds it. Hernias can appear as a slight lump or bulge under the skin. They usually develop in the groin or abdomen and may cause pain.


A goiter is an enlarged thyroid—a gland located in your neck that makes hormones to help control many functions in the body. A goiter appears as a swollen lump in the neck.

Though they’re usually harmless, some goiters are caused by thyroid cancer. For this reason, it’s important to see a healthcare provider if you develop a goiter.


Fibroadenomas are benign breast tumors that are usually:

  • Round
  • Painless
  • Firm
  • Smooth
  • Rubbery
  • Flat

When touched, fibroadenomas normally move easily. Sometimes no treatment is needed, but a surgeon may remove the noncancerous growth.


Hemorrhoids are swollen veins in the anus and lower rectum. If you have a hemorrhoid, you might feel a bulge or lump in these areas. You may also experience pain and swelling.


In rare cases, a lump under the skin can be cancerous. You may be able to feel cancerous growths under the skin in areas of the breast, testicles, neck, arms, or legs.

A type of skin cancer called soft tissue sarcoma can cause a cancerous lump to form almost anywhere on the body.

Testing a Lump

If a lump looks suspicious, a healthcare provider may order a biopsy to determine if it's cancerous. This involves removing a piece of tissue and sending it to a lab to analyze.

When to Worry vs. Not Worry 

While it’s hard not to worry, you should know that most skin lumps aren’t cause for concern.

Here are some signs that a suspicious lump could be harmful:

  • It abruptly becomes very hard and feels like a rock under the skin.
  • It grows quickly.
  • It starts to bleed.
  • It becomes a wound.

It’s always a good idea to see a healthcare provider any time you develop an unexplained lump on your skin. They can help determine whether it's serious or harmless.

Screening and Places to Look  

Skin lumps can form virtually anywhere on the body. It’s a good idea to perform frequent self-exams of your skin to look for any new or unusual lesions. Many healthcare providers recommend that you do a skin check once a month. For best results, skin exams should be performed in front of a mirror in a well-lit room. 


Finding a lump under the skin is a common occurrence and usually nothing to worry about. Lumps have different causes and can appear all over the body. Many benign lumps can be left alone, without any treatment.

Rarely will a bump turn out to be cancerous or another serious condition. Knowing the signs of a potentially dangerous growth can help you distinguish between a normal and abnormal lesion.

See a healthcare provider about a new or suspicious-looking growth. If it is cancer, catching it early on can improve your chances for successful treatment and a good outcome.

Frequently Asked Questions

  • Do cancerous lumps always hurt?

    No. Cancerous lumps are often painless. However, they can cause discomfort in some cases.

  • What size lumps are considered abnormal?

    Lumps can range from the size of a pea to larger than a golf ball. Lumps that are abnormal typically grow in size very rapidly.

  • What’s the difference between a cyst and tumor?

    A cyst is a sac that holds fluid, air, tissue, or another type of material. On the other hand, a tumor is generally a solid mass of tissue.

13 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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