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


  1. Broken bone. Medline Plus, a service of the National Library of Medicine National Institutes of Health. http://www.nlm.nih.gov/medlineplus/ency/article/000001.htm.
  2. Femur Shaft Fractures (Broken Thighbone). American Academy of Orthopaedic Surgeons. http://orthoinfo.aaos.org/topic.cfm?topic=A00521..


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.

... Read more about leg lumpintroduction


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:

Medical Reviewer: Cynthia Haines, MD Last Annual Review Date: Aug 5, 2013 Copyright: © Copyright 2014 Health Grades, Inc. All rights reserved. May not be reproduced or reprinted without permission from Health Grades, Inc. Use of this information is governed by the HealthGrades User Agreement.

This Article is Filed Under: Bones, Joints and Muscles

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