Differential Diagnoses for a Movable Cyst on the External Ear
The patient presents with a movable cyst on the external ear that has grown to the size of a dime, is red, sore to the touch, but not painful and less palpable. Based on these symptoms, the following differential diagnoses are considered:
- Single Most Likely Diagnosis
- Epidermoid Cyst (Sebaceous Cyst): This is the most likely diagnosis given the description of a movable, red, and sore cyst on the external ear. Epidermoid cysts are common, benign cysts that can occur on the skin, including the ear, and match the patient's symptoms.
- Other Likely Diagnoses
- Furuncle or Carbuncle: These are infections of the hair follicle that can present as red, sore, and swollen lesions. They could be considered given the redness and soreness of the cyst, although they are typically more painful.
- Cystic Acne: Although less common on the ear, cystic acne could present as a red, sore cyst. However, it would typically be associated with other acne lesions.
- Keratoacanthoma: A low-grade, benign tumor that can resemble a cyst and present as a firm, red nodule. It's less common but could be considered in the differential.
- Do Not Miss Diagnoses
- Basal Cell Carcinoma: Although rare, basal cell carcinoma can present as a red, sore lesion and must be considered to avoid missing a potentially serious diagnosis.
- Squamous Cell Carcinoma: Similar to basal cell carcinoma, squamous cell carcinoma is a type of skin cancer that could present with similar symptoms and must not be missed.
- Rare Diagnoses
- Branchial Cleft Cyst: A congenital anomaly that can present as a cyst on the neck or ear. It's less likely given the patient's age and the description, but could be considered in rare cases.
- Pilomatrixoma: A rare, benign tumor that can present as a firm, red nodule. It's less common and typically occurs in children, but could be considered in the differential diagnosis.