Differential Diagnosis for a Nodule Under the Skin on the Elbow
Single Most Likely Diagnosis
- Olecranon Bursitis: This condition is characterized by inflammation of the bursa at the elbow, leading to a swelling or nodule. It's a common issue, especially in individuals who frequently lean on their elbows or have experienced trauma to the area. The swelling can increase over time if the cause of the inflammation persists.
Other Likely Diagnoses
- Lipoma: A benign tumor composed of fat tissue, lipomas can occur under the skin in various parts of the body, including the elbow. They tend to grow slowly and are usually harmless.
- Epidermoid Cyst: Also known as sebaceous cysts, these are benign cysts that can form under the skin and may appear as a nodule. They can grow over time and may become inflamed.
- Ganglion Cyst: Although more common on the wrist, ganglion cysts can occur on the elbow. They are benign lumps filled with a jelly-like fluid and can change in size.
Do Not Miss Diagnoses
- Squamous Cell Carcinoma or Other Skin Cancers: While less common, any new or growing nodule under the skin should be evaluated for the possibility of skin cancer. Early detection is crucial for effective treatment.
- Infectious Abscess: An abscess is a collection of pus that has built up within the tissue of the body, indicating a bacterial infection. It can present as a growing nodule and requires prompt medical attention to prevent the spread of infection.
- Rheumatoid Nodule: Associated with rheumatoid arthritis, these nodules can form under the skin, especially over bony prominences like the elbow. They indicate a more severe disease process.
Rare Diagnoses
- Pilomatrixoma: A rare, benign tumor of the skin, often presenting as a hard, mobile nodule. It's more common in children but can occur at any age.
- Dermatofibroma: A benign skin growth that can appear as a firm nodule, usually after minor injury, and can grow over time.
- Neurofibroma: A benign tumor of the nerve tissue, which can present as a nodule under the skin. It's associated with neurofibromatosis type 1 (NF1) in some cases.