Last updated November 14, 2020
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Painless Lump in the Knee
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Last updated November 14, 2020
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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.
Painless knee lump questionnaire
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6 causes of 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
Painless knee lump questionnaire
Use our free symptom checker to find out what's causing your lump.
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.
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
Painless knee lump questionnaire
Use our free symptom checker to find out what's causing your lump.
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?
Self-diagnose with our free Buoy Assistant if you answer yes on any of these questions.
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 Buoy Assistant.
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