Dr Shayan Ahmed

Forearm Lumps: Causes, symptoms and how an ultrasound can help with diagnosis

November 22, 2023, 22:11

Forearm lumps can have a broad range of causes and symptoms. If you’ve found lumps in your forearm, early diagnosis by an elbow and forearm ultrasound is the first step along your road to recovery.

What Are the Most Common Forearm Lump Causes and Their Symptoms?

Most of the time, forearm lumps turn out to be benign (non-cancerous) growths (1). Although cancerous conditions are rare, it’s always prudent to seek medical advice at the outset. The earlier the intervention, the better your chances of a positive outcome, even if the lump turns out to be malignant.

Knowing the causes and symptoms of the most common forearm lumps can help you discuss your condition with your doctor with greater confidence. Let’s look at some of the issues that may have caused the lump in your forearm.


These soft, moveable lumps occur when fat accumulates between the layers of muscles in your forearm and your skin (2). Usually, the only symptom is the appearance of the lump itself. Risk factors for lipomas include being 40 and 60 years old or having a family history of the condition (3).

Lipomas are benign, but they can cause discomfort if the tumour affects nearby nerves. If that’s the case, your doctor might recommend surgery to remove it. Otherwise, lipomas require no treatment at all.

Skin Abscesses

Abscesses occur when pus from a bacterial infection collects beneath the skin (4). These painful lumps usually feel warm to the touch, with redness surrounding the area.

Some smaller abscesses resolve on their own. Others require treatment with antibiotics or an incision and drainage (I & D) procedure (5). If you experience fever or chills, it’s imperative that you seek treatment quickly, lest the infection spread into your bloodstream.


Caused by exposure to the human papillomavirus (HPV), these lumps appear as small, raised bumps in your skin (6). Some warts have tiny blood vessels inside them, giving them a dotted appearance. Other symptoms include itching, pressure, and tightness in the skin surrounding the wart.

Although warts are usually benign, it pays to seek medical advice since they are contagious. If you choose an over-the-counter treatment, avoid touching others with the affected forearm so you don’t spread the virus.


Dermatofibromas are hard, often painful skin tumours that develop just beneath the skin, usually on the extremities, such as your forearm (7). Usually, they are benign, but since some develop into malignancies, it pays to schedule an ultrasound exam to rule out cancer.

Risk factors for dermatofibromas include being female, having an injury to the skin from a spider bite, having a tattoo or skin testing, or having a history of folliculitis. Unless the tumour causes significant discomfort or presents a risk of malignancy or another serious condition, surgical removal is often unnecessary.

Swollen Lymph Nodes

When you have an infection, your body rises to the occasion, producing antibodies to fight off the invading germs. (8) Your lymphatic system plays a major role in that fight – sending germ-killing white blood cells to the rescue.

For that reason, your lymph nodes can become swollen and often sore. These lumps usually disappear after the infection subsides. If they remain swollen, it’s time to see your doctor. Swollen lymph nodes that persist long after the infection is gone can be a sign of leukaemia or another serious condition.

Ganglion Cysts

Ganglion cysts are fluid-filled, somewhat moveable lumps that form under your skin, usually near joints, such as your wrist or elbow (9). Most of the time, you’ll experience no symptoms except for the lump itself.

  • Risk factors for ganglion cysts include:

  • Being female

  • Having a previous joint injury

  • Being between 20 and 50 years old

Having arthritis These cysts are benign and often go away on their own. However, if the cyst presses against nerves or the joint itself, causing pain and interfering with movement, your doctor may suggest a surgical procedure to remove it. Your doctor can usually perform this surgery – a ganglionectomy – on an outpatient basis.


Although an angiolipoma is a subtype of lipoma, it differs from other lipomas in two significant aspects (10). First, it’s most common in young people between 20 and 30 years of age rather than middle-aged patients. Secondly, angiolipomas contain blood vessels as well as fat.

Angiolipomas are relatively rare and occur in two types:

  • Non-infiltrating angiolipomas: Although this type of angiolipoma can be painful, it doesn’t extend deep into the skin. This type of angiolipoma is the more common of the two.

  • Infiltrating angiolipomas: These rare yet benign tumours extend more deeply into your forearm, often into your muscles, fibrous tissue, or fat. Usually, infiltrating angiolipomas are painless. Angiolipomas appear as round, spongy lumps, often occurring in groups. They’re often painful to the touch and can cause swelling and discolouration in the immediate area. In addition to age, risk factors include:

  • Corticosteroid use: Prolonged usage of corticosteroids, such as skin ointments and creams, increases your risk of angiolipomas.

  • A diagnosis of diabetes: People with diabetes are at a higher risk of developing angiolipomas than other populations.

  • A family history of angiolipomas: Genetics often play a role in your likelihood of developing these tumours.

  • A history of repetitive though minor injuries: Repetitive injuries can also trigger a response in your body, such as an angiolipoma.

Most angiolipomas don’t require treatment. However, if the angiolipomas cause you pain or interfere with movement, outpatient surgery is an option.


Although rare, liposarcomas often resemble angiolipomas (11). For that reason, an ultrasound examination is a must, even if you believe your tumour is an angiolipoma.

Like lipomas, liposarcomas start in your fat cells. However, some types of liposarcomas can spread from your arm to vital organs – so it’s essential that you seek treatment at the earliest sign of a problem.

Early liposarcoma symptoms include:

  • A new or fast-growing, rubbery lump under your skin

  • Weakness in the arm that has the lump

Later, when the disease has spread to other organs, symptoms can include bowel issues, loss of appetite, shortness of breath, or bloody vomiting.

Depending on the stage at which your doctor diagnoses your liposarcoma, treatment might include surgery, radiation therapy, or chemotherapy.

What Kinds of Lumps in the Forearm Can Doctors Detect with an Ultrasound Scan?

An ultrasound can help your doctor find signs of inflammation and fluid that indicate the types of repetitive injuries that give rise to angiolipomas, ganglion cysts, and other injury-induced forearm lumps. Ultrasound exams can also help your specialist diagnose masses, tumours, and other abnormalities in their early stages, giving you the best chance at a complete recovery.

What Will Happen During My Elbow and Forearm Ultrasound?

Ultrasound examinations are non-invasive, causing you no pain or discomfort. However, your specialist will use a water-soluble gel during the procedure, so it is wise to wear a short-sleeved or sleeveless top to the exam. If you have jewellery, be sure to remove it before the procedure.

When you arrive, the staff will take you to the examination room. There, your specialist will direct you to position your forearm on the exam table. Then, they will apply the gel to help the ultrasound probe to glide over your skin to give the specialist accurate images of your forearm lump as they move the probe over the lump.

When you choose the Harley Street Ultrasound Group for your ultrasound procedure, your doctor will provide you with the results immediately. In most cases, the specialist can narrow down a diagnosis during the same visit.

If your forearm lump requires treatment, the doctor will ask you to schedule a follow-up appointment with the staff. Since the procedure is completely safe and requires no anaesthesia, you can return to work or home after your consultation.

Your peace of mind is paramount at the Harley Street Ultrasound Group. If you’ve found a lump on your forearm, an early diagnosis is the best way to prevent more serious issues. Schedule your forearm ultrasound with our compassionate staff today.

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