Arm Lump

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What is arm lump?

An arm lump is a protuberance or localized area of swelling occurring on the arm. Other terms used to describe the various types of lumps include bump, nodule, contusion, tumor and cyst. Arm lumps can be caused by any number of conditions, including infections, inflammation, tumors or trauma. Depending on the cause, lumps may be single or multiple, soft or firm, painful or painless. They may grow rapidly or may not change in size.

Arm lumps due to local infectious causes may appear as boils, or abscesses. Many types of infections cause the lymph nodes to enlarge and feel like lumps, most commonly in the armpits. Traumatic causes of arm lumps range from bug bites to severe injuries that can produce a localized collection of blood in the tissues (hematoma).

Both benign and malignant tumors of the skin, soft tissues, or bones of the arm can sometimes feel like lumps. In these cases, either a biopsy or surgical removal of the arm lump can determine whether cancer is present. Cysts, which are fluid-filled, sac-like structures that can form in various parts of the body, often feel like lumps. Some cysts may be present at birth, while others develop as a result of inflammation, tumors, or wear-and-tear over time.

Conditions that produce inflammation throughout the body, such as rheumatoid arthritis (chronic autoimmune disease characterized by joint inflammation), may be associated with arm lumps.

Lumps caused by infection, inflammation or trauma are usually temporary and subside as the underlying condition resolves. Lumps that persist or continue to grow over time may signal more serious conditions, such as tumors. If you have any lump that is persistent or causes you concern, seek prompt medical care.


What other symptoms might occur with arm lump?

Arm lumps may accompany other symptoms, depending on the underlying disease, disorder or condition. Symptoms that cause arm lumps may also involve other body systems.

Related localized symptoms that may occur along with an arm lump

An arm lump may be accompanied by other localized symptoms including:

  • Bleeding or bruising
  • Pus or discharge
  • Redness and warmth
  • Tenderness or pain

Other symptoms that may occur along with an arm lump

An arm lump may accompany symptoms related to other body systems including:

Symptoms that might indicate a serious condition

In some cases, arm lumps might indicate a serious condition that should be immediately evaluated in an emergency setting. Seek immediate medical care (call 911) if you, or someone you are with, have arm lumps along with other serious symptoms including:

  • Fever and chills
  • Profuse or uncontrollable bleeding
  • Rapid heart rate (tachycardia)
  • Red streaks that extend up the arm


What causes arm lump?

Arm lumps have many possible causes, including trauma, infections, inflammatory diseases, benign cysts and tumors, and cancers.

Traumatic causes of arm lumps

Minor and severe injuries, as well as internal trauma, can result in a localized swelling or lump on the arm including:

  • Broken bones

  • Hematoma (collection of blood in body tissues)

  • Sting or bite injuries

Infectious causes of arm lumps

An infection may produce one or more lumps in the form of a localized abscess or as a diffuse enlargement of lymph nodes in the arm. Infectious causes of lumps include:

  • Abscesses

  • Cellulitis (infection of the skin and tissue beneath the skin)

  • Papilloma virus infections (warts)

Inflammatory causes of arm lumps

Some conditions that lead to inflammation in the body may produce arm lumps including:

  • Gout (a type of arthritis caused by a buildup of uric acid in the joints)

  • Osteoarthritis (type of arthritis characterized by degeneration of the cartilage and bone in the joints)

  • Rheumatic fever (disease characterized by inflammation of the joints and of the connective tissue, especially in the blood vessels and heart)

  • Rheumatoid arthritis (chronic autoimmune disease characterized by joint inflammation)

Tumors that can cause arm lumps

Both benign and malignant tumors can cause arm lumps including:

  • Fibroma (benign tumor composed of fibrous or connective tissue)

  • Lipoma (benign fatty growth)

  • Lymphoma (cancer of the lymphatic system)

  • Melanoma (cancer arising in the melanocytes, or pigment-producing cells, in the skin or other parts of the body)

  • Nevi (moles of the skin)

  • Nonmelanoma skin cancers

Serious or life-threatening causes of arm lumps

In some cases, arm lumps may be a symptom of a serious or life-threatening condition that should be immediately evaluated by a health care provider. These include:

  • Abscess with spreading infection

  • Cancer

  • Fracture of bone

  • Joint dislocation

Questions for diagnosing the cause of a lump

To diagnose your condition, your doctor or licensed health care practitioner will ask you several questions related to your arm lump including:

  • How long have you had the arm lump?

  • Are you experiencing any other symptoms along with the arm lump?

  • Is the lump getting bigger?

  • Is the lump painful?

  • Do you have lumps anywhere else on your body?

What are the potential complications of arm lump?

Arm lumps caused by cancer may have life-threatening consequences, depending on the type and stage (extent) of the cancer. Left untreated, lumps due to abscesses or serious infections may lead to widespread infection in the body. Following your treatment plan for serious causes of lumps can help reduce your risk of complications including:

  • Joint destruction and deformity

  • Necrosis of tissue or gangrene

  • Spread of cancer

  • Spread of infection

  • Ulceration or skin infection

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Medical Reviewer: William C. Lloyd III, MD, FACS
Last Review Date: 2018 Dec 21
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