Differential Diagnosis for Movable Lesion on Back of Scalp

• Single most likely diagnosis
  • Lipoma: A benign tumor composed of fat tissue, lipomas are common, movable, and often found on the scalp. They are usually soft, painless, and can be freely movable under the skin.
• Other Likely diagnoses
  • Epidermoid cyst: Also known as sebaceous cysts, these are benign, usually movable lesions that can occur on the scalp. They are filled with a cheesy material and can become inflamed.
  • Dermatofibroma: A small, hard bump that can appear on the scalp, dermatofibromas are benign growths that can be movable. They are often the result of a minor injury, which leads to the accumulation of fibroblasts.
  • Neurofibroma: A type of tumor that arises from the nerve tissue, neurofibromas can be movable and are found on the scalp. They are more common in individuals with neurofibromatosis type 1.
• Do Not Miss (ddxs that may not be likely, but would be deadly if missed.)
  • Metastatic lesion: Although rare, a movable lesion on the scalp could be a metastasis from another cancer, such as breast, lung, or melanoma. Early detection is crucial for treatment and prognosis.
  • Squamous cell carcinoma or basal cell carcinoma: While less common on the scalp, these skin cancers can present as movable lesions. They require prompt diagnosis and treatment to prevent spread and complications.
• Rare diagnoses
  • Pilomatrixoma: A rare, benign tumor of the hair follicle, pilomatrixomas can appear on the scalp as movable, firm lesions. They are more common in children and young adults.
  • Osteoma cutis: A rare condition where bone forms in the skin, osteoma cutis can present as a movable lesion on the scalp. It can be primary (without a known cause) or secondary, associated with other conditions.