Differential Diagnosis for a Mass on the Head with Hair Growing Out

• Single most likely diagnosis
  • Dermoid cyst: This is a common diagnosis for a mass on the head with hair growing out, as dermoid cysts can contain skin, hair, and other tissue.
• Other Likely diagnoses
  • Pilar cyst: These cysts can occur on the scalp and may have hair growing out of them.
  • Epidermoid cyst: Similar to dermoid cysts, epidermoid cysts can contain skin and hair, making them a possible diagnosis.
  • Trichilemmal cyst: These cysts are also found on the scalp and can have hair growing out of them.
• Do Not Miss diagnoses
  • Malignant tumor (e.g., squamous cell carcinoma, basal cell carcinoma): Although less likely, it's crucial to rule out malignant tumors, as they can be life-threatening if left untreated.
  • Infectious abscess: An abscess on the scalp can cause a mass and may have hair growing out of it, but it requires prompt treatment to prevent complications.
• Rare diagnoses
  • Teratoma: A type of tumor that can contain several different types of tissue, including hair, making it a rare but possible diagnosis for a mass on the head with hair growing out.
  • Neurofibroma: A rare tumor that can occur on the scalp and may have hair growing out of it, often associated with neurofibromatosis type 1.