Differential Diagnosis for a Lump on the Arm
- Single Most Likely Diagnosis
- Lipoma: A benign tumor composed of fat tissue, which is the most common cause of a lump on the arm. It is usually soft, movable, and painless.
- Other Likely Diagnoses
- Cyst: A fluid-filled sac that can form on the arm, often due to a blocked oil gland or hair follicle. It may be tender to the touch and can become infected.
- Abscess: A collection of pus that has built up within the tissue of the arm, often caused by a bacterial infection. It is typically painful, red, and swollen.
- Hematoma: A collection of blood outside of blood vessels, often caused by trauma to the arm. It can be painful and may feel firm or soft to the touch.
- Do Not Miss Diagnoses
- Soft tissue sarcoma: A rare type of cancer that can cause a lump on the arm. Although it is unlikely, it is crucial to consider this diagnosis to ensure prompt treatment if necessary.
- Infected sebaceous cyst: An infected cyst can lead to serious complications, such as abscess formation or sepsis, if left untreated.
- Lymphoma: A type of cancer that can cause lymph nodes to become enlarged, forming a lump on the arm. It is essential to consider this diagnosis to ensure timely treatment.
- Rare Diagnoses
- Dermatofibroma: A rare, benign skin growth that can cause a lump on the arm. It is usually firm and may be itchy or tender to the touch.
- Neurofibroma: A rare, benign tumor that arises from nerve tissue and can cause a lump on the arm. It is often associated with neurofibromatosis type 1.
- Epidermoid cyst: A rare, benign cyst that can form on the arm, often due to a blocked hair follicle or oil gland. It may be tender to the touch and can become infected.