Differential Diagnosis for a 19-year-old Female with a History of Subdermal Cysts
- Single most likely diagnosis:
- Epidermoid cysts: These are the most common type of subdermal cysts, often presenting as firm, mobile, and sometimes tender nodules under the skin. They are usually benign and can be caused by blocked oil glands or trauma.
- Other Likely diagnoses:
- Pilar cysts: Also known as trichilemmal cysts, these are similar to epidermoid cysts but tend to occur on the scalp. They are also benign and can be hereditary.
- Sebaceous cysts: While often used interchangeably with epidermoid cysts, true sebaceous cysts originate from the sebaceous glands and can also present as subdermal nodules.
- Folliculitis or infected hair follicles: These can sometimes present as cyst-like lesions, especially if they become infected and form an abscess.
- Do Not Miss diagnoses:
- Metastatic disease: Although rare, it's crucial not to miss the possibility of metastatic cancer presenting as subdermal cysts, especially if there's a known history of cancer.
- Infectious diseases (e.g., tuberculosis, actinomycosis): These can cause chronic infections that might present with cyst-like lesions under the skin.
- Sarcoidosis: A systemic disease that can cause granulomatous inflammation, sometimes presenting as skin nodules or cysts.
- Rare diagnoses:
- Steatocystoma multiplex: A rare genetic disorder characterized by multiple seabaceous cysts.
- Dermoid cysts: These are teratomas that can occur under the skin, containing various types of tissue like hair, teeth, or bone.
- Eruptive vellus hair cysts: A rare condition where multiple small cysts filled with vellus hair appear, usually on the chest or abdomen.