Symptoms A-Z

Painless Lump in The Knee Symptoms, Causes & Common Questions

The usual cause for a painless bump on the knee derives from skin conditions like cysts, warts, or abscesses. Other causes for a lump on the knee with no pain include non cancerous skin growths. Read now for more information on causes and how to get rid of painless lumps on the knee.

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6 Possible Painless Lump In The Knee Causes

The list below shows results from the use of our quiz by Buoy users who experienced painless lump in the knee. 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

Dermatofibroma

A dermatofibroma is a common skin growth that usually appears on the lower legs, but may appear anywhere on the body. These growths are benign (noncancerous). Dermatofibromas are most common in adults and are rarely found in children.

Symptoms include a hard, raised growth that is red, pink, ...

Wart

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.

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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

Baker's cyst (popliteal cyst)

A Baker's cyst, also called as Popliteal cyst, is a fluid-filled mass that causes a bulge and a feeling of tightness behind the knee. The pain can get worse when the knee is fully flexed or extended.

Rarity: Uncommon

Top Symptoms: calf pain, swollen knee, knee pain that gets worse when squatting, knee instability, dull, achy knee pain

Symptoms that always occur with baker's cyst (popliteal cyst): lump on the back of the knee, constant knee lump

Urgency: Primary care doctor

Synovial chondromatosis

Synovial chondromatosis is a disease affecting the synovium, which is a thin flexible membrane around a joint. It can often be confused with tendinitis and/or arthritis.

Rarity: Ultra rare

Top Symptoms: joint swelling, pain in one knee, pain in one hip, swollen knee, spontaneous knee pain

Symptoms that always occur with synovial chondromatosis: joint swelling

Symptoms that never occur with synovial chondromatosis: fever, night sweats, unintentional weight loss, warm red ankle swelling, warm red knee swelling, warm and red elbow swelling

Urgency: Primary care doctor

Questions Your Doctor May Ask About Painless Lump In The Knee

To diagnose this condition, your doctor would likely ask the following questions:

  • What color is the bump?
  • Is your bump getting bigger?
  • Is there anything on the surface of the bump?
  • Any fever today or during the last week?

The above questions are also covered by our A.I. Health Assistant.

If you've answered yes to one or more of these questions

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Painless Lump In The Knee Symptom Checker Statistics

People who have experienced painless lump in the knee have also experienced:

  • 18% Knee Bump
  • 7% Pain In The Outside Of The Knee
  • 7% Soft, Knee Lump

People who have experienced painless lump in the knee were most often matched with:

  • 100% Wart

People who have experienced painless lump in the knee had symptoms persist for:

  • 39% Over a month
  • 25% Less than a week
  • 15% Less than a day

Source: Aggregated and anonymized results from visits to the Buoy AI health assistant (check it out by clicking on “Take Quiz”).

Painless Lump In The Knee Symptom Checker

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Disclaimer: The article does not replace an evaluation by a physician. Information on this page is provided as an information resource only, and is not to be used or relied on for any diagnostic or treatment purposes.