Lump on Biceps under skin: Causes, Symptoms, Diagnosis, Treatments

The bicep is a muscle located in the upper arm, from the shoulder to the elbow. The muscle is involved in a lot of weight lifting, especially for body builders and manual workers. A lump on the bicep under the skin may result from a form of injury to the muscle, a benign growth, or from malignant cancer growths.

Most of the lumps that will form on the bicep under the skin can be left without treatment. In most cases, they will heal on their own. All the same, it is very important to understand when a lump is harmless and when it is not. This article discusses, Lump on Biceps under skin: Causes, Symptoms, Diagnosis and Treatments.

Possible causes of lump on bicep under skin

Any of the following may be responsible for a lump on the bicep under the skin:


Cysts are the most common general causes of lumps under the skin. A cyst forms when fluid, gas, pus or soft tissue becomes enclosed in a sac under the skin. They are generally harmless and painless. On the bicep, just about the shoulder, a ganglion cyst may develop. Ganglion cysts are filled with a jellylike fluid and mostly originate from joints or tendons. They are common causes of hard lump on top of foot.  Some cysts produce a foul odor even when not drained.

Injuries and trauma

It is expected that the bicep will recurrently sustain an injury or a form of trauma. Injuries can cause muscle strains or even bone fractures. Traumas will damage the skin, possibly leading to an infection, allergic reaction or irritation. This is very common in athletes and body builders who may spend long hours in sleeveless shirts.

Benign tumors

There are many growths that can occur under the skin but considered benign. A benign growth will not spread its cells to other parts of the body. It is the main difference between cancerous and benign tumors. Examples in this category include lipomas, fibromas, bone spurs and more.

Cancer tumors

Cancer develops when normal body cells mutate and start dividing abnormally fast. With time, too many cells will be given rise to, which leads to formation of a tumor. The problem with malignant cancer cells is that they keep spreading to other body parts. This means that you may succeed in treating one tumor, just to be left with several others in different parts of the body. Chances are that a patient will succumb to any one or several of the remaining tumors. Malignant cancer cells can start anywhere in the body, including under the skin. In fact, even a hard lump in the earlobe could be a malignant cancer tumor.

Lump on bicep under skin due to injuries or trauma

Below are conditions that can cause lump on bicep under skin due to injuries and trauma. You can get more information on any one of them online.

Biceps rupture

As the name suggests, a biceps rupture occurs when a tendon tears and snaps. Tendons are the structures that attach your biceps to bones. Biceps rupture is a painful condition and likely to result in a lump on the bicep.

Diagnosis can be done by comparing the symptoms and physical examination. If necessary, x-rays and MRIs will be used. Treatment for simple biceps rupture need not be complicated. They include:

  • Ice treatment
  • Rest
  • Anti-inflammatory medications (non-steroidal)
  • Surgery (for severe tendon tears)


If you have a lump on the bicep under the skin that is close to the shoulder or elbow joint and causing pain or stiffness when moving the arm, it could be due to tendinitis. It is an inflammation of the tendons, mostly due to irritation or overuse.

Diagnosis can be done through x-ray and MRI imaging. A doctor can sometimes recognize tendinitis by checking the symptoms. Treatments include:

  • OTC painkillers
  • Splinting
  • Cold or warm compress
  • Rest

Muscle strain

Muscle strain develops when your muscles are overused, injured or forced to carry out a physical activity. This can happen over time or suddenly.

Diagnosis can be done with X-ray and MRIs. Treatment revolves around allowing enough time for the strained muscle to recover naturally. Some pain killers and non-steroidal medications may help. Your doctor may also consider splinting the strained muscle. At home, try treatment with warm and cold compresses.


A hematoma occurs due to accumulation of blood under the skin, mostly after a form of injury. This happens when a blood vessel ruptures and releases blood to surrounding skin layers.

Hematomas go away on their own and don’t require treatment. You can however apply hot compress to encourage liquefaction of clotted blood.

Bone infection

The bone neighboring the biceps at shoulder or elbow joint may develop a bone infection known as osteomyelitis. It is a painful condition and will lead to swelling and reddening of the bicep.

Bone fracture

A fractured bone is usually very painful and easily noticeable. For one, it will cause a lump on the bicep just above it. It will also be impossible to perform activities such as lifting objects with the affected arm.

Insect bites and irritation

An insect bite will irritate the skin or cause an allergic reaction. Lumps that develop will mostly be surrounded by red, irritated and inflamed skin.

Benign tumors that may cause lump on bicep under skin


Lipomas are soft lumps that form under the skin. They basically are fat nodules which feel rubbery and movable to touch. Lipomas are harmless, painless and require no treatment.


Fibromas are defined as a disorder of the connective tissue. Dermatofibromas are red, hard, small lumps that form mostly on the arms and legs. Like lipomas, they are harmless and in need of no special treatment.

Rheumatoid nodules

These are common in individuals diagnosed with rheumatoid arthritis. They form lumps that feel firm, fixed and hard to touch. Most of them will occur just about the affected joint. A painful lump on the back of the leg behind the knee can also be rheumatoid nodule.

Cutaneous neurofibroma

These are small lumps that originate from small nerves just under the skin. The lumps are in most cases itchy but not cancerous.

Lump on bicep under skin due to cancer

As mentioned earlier, cancer cells can start or migrate to the biceps. This can be encouraged by the presence of lymph nodes in the armpits. Stage II cancers mostly invade the lymphatic system. They can eventually settle on any organ or body part close to the lymph nodes. Symptoms such as a lump in the throat when swallowing or painful lumps on the groin area are common with Stage II cancer.

Cancer lumps are generally hard, immovable, firm and painless, especially in the initial stages. They continuously increase in size and are usually irregularly shaped at the edges.

Stage III cancers, the most dangerous stage, spread to other body parts and organs. Signs of spreading cancer include:

  • Lumps elsewhere in the body
  • Headaches
  • Confusion
  • Pain in lower abdomen
  • Chronic cough
  • Sudden weight loss
  • Poor healing of wounds
  • Weakened immunity

Talk to your doctor if a lump appears under the skin on your biceps and persists for more than two weeks. This is especially if the lump is painless and continues to increase in size. You can also find it helpful to learn more information and watch videos related to topics such as how to check the breasts for lumps, meaning of a pea-sized lump on the testicles and so on.