Medical Causes of a Lump in Your Leg and Related Symptoms

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What is a leg lump?

A lump is a bump, nodule, tumor, or localized area of swelling that can occur anywhere on your body. Leg lumps can be caused by any number of conditions, including infections, inflammation, tumors and trauma. Depending on the cause, leg lumps may be single or multiple, soft or firm, painful or painless. They may grow rapidly or may not change in size.

Leg lumps due to local infectious causes may appear as boils, abscesses, or swollen areas. Traumatic causes of lumps range from bug bites to severe injuries that can produce a hematoma (collection of blood in body tissues). Conditions that produce inflammation throughout the body, such as rheumatoid arthritis (chronic autoimmune disease characterized by joint inflammation), may be associated with lumps, particularly around your knee joint. Lumps in the knee area can result from the many different kinds of arthritis or from injuries to the joint.

While these conditions are rare, both benign and malignant tumors of the skin, soft tissues, or bones can sometimes feel like leg lumps. In these instances, a biopsy or surgical removal of the lump can determine whether the tumor is cancerous.

In some cases, a lump may occur with other symptoms that might indicate a serious or life-threatening condition that should be immediately evaluated. Seek immediate medical care (call 911) if you, or someone you are with, have any of the following symptoms: paralysis or inability to move a body part, loss of sensation, absent pulses in the feet, uncontrolled or heavy bleeding, high fever (higher than 101 degrees Fahrenheit), or uncontrollable pain.

If your leg lump persists or causes you concern, seek prompt medical care.

What other symptoms might occur with a leg lump?

A leg lump may accompany other symptoms, which vary depending on the underlying disease, disorder or condition. Conditions that result in a leg lump may also involve other body systems.

Localized symptoms that may occur along with a leg lump

A leg lump may be accompanied by other symptoms in or around the leg including:

  • Bleeding or bruising
  • Deformity or instability of the knee joint
  • Leg pain and swelling
  • Pus or discharge
  • Redness and warmth
  • Tenderness

Other symptoms that may occur along with a leg lump

A leg lump may be accompanied by symptoms that are not in or around the leg including:

  • Fever
  • Lumps elsewhere on the body
  • Muscle weakness
  • Pain or swelling in other joint
  • Weight loss

Symptoms that might indicate a serious condition

In some cases, a leg lump may occur with other symptoms, especially those related to injury, which might indicate a serious or life-threatening condition that should be immediately evaluated. Seek immediate medical care (call 911) if you, or someone you are with, have any of the following symptoms:

  • Coldness of the feet, with weak or absent pulse
  • High fever (higher than 101 degrees Fahrenheit)
  • Loss of sensation in the lower leg
  • Obvious breakage or deformity of the bones
  • Paralysis or inability to move a body part
  • Uncontrollable pain
  • Uncontrolled or heavy bleeding or hemorrhage

What causes a leg lump?

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

Traumatic causes of a leg lump

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

  • Broken bones
  • Hematoma (collection of blood in body tissues)
  • Knee injury
  • Sting or bite injuries

Infectious causes of a leg lump

An infection may produce a lump in the form of a localized abscess or boil. Infectious causes of lumps include:

  • Abscesses
  • Boils
  • Cellulitis (infection of the skin and underlying tissues)
  • Osteomyelitis (bone infection)
  • Papillomavirus infections (warts)

Inflammatory causes of a leg lump

Some conditions that lead to inflammation in the body may produce leg lumps, particularly around the knee joint including:

  • Erythema nodosum (disorder that causes tender red lumps beneath the skin surface)
  • Gout (type of arthritis caused by a buildup of uric acid in the joints) and pseudogout
  • Osteoarthritis
  • Psoriatic arthritis (arthritis associated with psoriasis of the skin)
  • Rheumatoid arthritis (chronic autoimmune disease characterized by joint inflammation)
  • Systemic lupus erythematosus (disorder in which the body attacks its own healthy cells and tissues)

Tumors that can cause a leg lump

Both benign and malignant tumors can cause 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
  • Osteosarcoma (type of bone cancer)
  • Sarcoma (soft-tissue cancerous tumor)

Serious or life-threatening causes of a leg lump

In some cases, a leg lump may be a symptom of a serious or life-threatening condition including:

  • Bone or soft-tissue cancers
  • Osteomyelitis (bone infection)
  • Septic arthritis (infectious arthritis)

Questions for diagnosing the cause of a leg lump

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

  • How long have you felt your leg lump?
  • Is the lump getting bigger?
  • Is the lump painful?
  • Is the lump the result of an injury?
  • Do you have any other symptoms?

What are the potential complications of a leg lump?

Lumps caused by cancers may have life-threatening consequences, which depend 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. Leg lumps and associated symptoms can rarely be due to serious diseases, so failure to seek treatment can result in serious complications and permanent damage.

Once the underlying cause is diagnosed, it is important for you to follow the treatment plan that you and your health care professional design specifically for you to reduce the risk of potential complications including:

  • Decreased athletic performance
  • Disability
  • Joint deformity and destruction
  • Nerve problems that cause pain, numbness or tingling
  • Permanent or chronic pain
  • Spread of cancer
  • Spread of infection
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Medical Reviewer: William C. Lloyd III, MD, FACS
Last Review Date: 2020 Dec 3
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THIS TOOL DOES NOT PROVIDE MEDICAL ADVICE. It is intended for informational purposes only. It is not a substitute for professional medical advice, diagnosis or treatment. Never ignore professional medical advice in seeking treatment because of something you have read on the site. If you think you may have a medical emergency, immediately call your doctor or dial 911.
  1. Broken bone. Medline Plus, a service of the National Library of Medicine National Institutes of Health.
  2. Femur Shaft Fractures (Broken Thighbone). American Academy of Orthopaedic Surgeons.