Differential Diagnosis for a Lump on the Scalp
- Single Most Likely Diagnosis
- Seborrheic keratosis: A common, benign skin growth that can appear on the scalp, often due to aging and sun exposure. It's usually harmless but can be removed for cosmetic reasons.
- Other Likely Diagnoses
- Cyst (epidermoid or pilar): Benign cysts that can form on the scalp due to blocked oil glands or hair follicles. They can become inflamed or infected.
- Lipoma: A benign tumor composed of fat tissue, which can occur on the scalp. It's usually soft and movable.
- Dermatofibroma: A small, hard bump that can develop on the scalp after a minor injury, likely resulting from the clustering of immune cells and fibroblasts.
- Do Not Miss Diagnoses
- Squamous cell carcinoma: A type of skin cancer that can appear on the scalp, especially in areas exposed to the sun. Early detection is crucial for effective treatment.
- Basal cell carcinoma: The most common form of skin cancer, which can also occur on the scalp. It's usually slow-growing but can be destructive if left untreated.
- Metastatic tumor: Although rare, a lump on the scalp could be a metastasis from another cancer, such as breast, lung, or melanoma. This would be particularly concerning in patients with a known history of cancer.
- Rare Diagnoses
- Pilomatrixoma: A rare, benign tumor that originates from the hair follicle matrix. It's more common in children and young adults.
- Trichoepithelioma: A rare, benign tumor of hair follicle origin, which can appear on the scalp. It may be solitary or multiple.
- Angiolipoma: A rare, benign tumor composed of blood vessels and fat tissue. It can occur on the scalp and may be painful due to its vascular nature.