Differential Diagnosis for a Lump on the Arm Hurting for 5 Months
Single Most Likely Diagnosis
- Lipoma: A benign tumor composed of fat tissue, which is common and can cause a lump that may be painful if it presses on nearby nerves or has grown large enough to cause discomfort.
Other Likely Diagnoses
- Cyst: Such as an epidermoid cyst or sebaceous cyst, which can become inflamed and painful.
- Abscess: A collection of pus that has built up within the tissue of the arm, often caused by a bacterial infection, which can be painful and form a lump.
- Hematoma: A collection of blood outside of blood cells, which can occur after an injury and may cause a painful lump.
- Infected or inflamed lymph node: Can cause a painful lump in the arm, especially if there's an underlying infection.
Do Not Miss Diagnoses
- Soft tissue sarcoma: Although rare, this is a type of cancer that originates in the soft tissues (such as muscles, fat, blood vessels, and tendons) and can present as a painful lump. Early detection is crucial.
- Metastatic tumor: A tumor that has spread from another part of the body to the arm, which could present as a lump and may be painful.
- Osteosarcoma: A type of bone cancer that could cause a lump and pain in the arm if the tumor is located near the surface of the bone.
Rare Diagnoses
- Neurofibroma: A benign tumor of the nerve tissue, which can cause a lump and may be painful if it presses on the nerve.
- Giant cell tumor: A rare, benign tumor that typically occurs in the bone but can extend into the soft tissue, causing a lump.
- Myositis ossificans: A condition where there is heterotopic ossification of soft tissue (usually muscle), which can form a painful lump after trauma.
- Pilomatrixoma: A rare, benign skin tumor that originates from the hair follicle matrix and can cause a lump, sometimes painful.