Differential Diagnosis for a 0.5 cm Non-Movable Mass Behind the Earlobe

• Single Most Likely Diagnosis
  • Benign cyst or epidermoid cyst: This is a common finding in the area behind the earlobe. The description of the mass being non-movable and slightly tender to the touch (ttt) aligns with the presentation of a benign cyst, which can become inflamed or infected, causing tenderness.
• Other Likely Diagnoses
  • Lipoma: A lipoma is a benign tumor composed of fat tissue. It can present as a small, non-movable mass and is commonly found in subcutaneous tissues, including behind the ear.
  • Sebaceous cyst: Similar to epidermoid cysts, sebaceous cysts are benign and can appear as non-movable masses. They are filled with a cheesy, semi-solid material and can become inflamed.
  • Abscess or infected gland: An abscess or infected gland in the area could present as a tender mass. However, it would typically be more fluctuant and have a greater degree of tenderness.
• Do Not Miss Diagnoses
  • Malignant tumor (e.g., basal cell carcinoma, squamous cell carcinoma): Although less likely, it is crucial not to miss a malignant tumor. These can present as non-healing ulcers or firm masses and require early diagnosis for effective treatment.
  • Parotid gland tumor: Tumors of the parotid gland, whether benign (like pleomorphic adenoma) or malignant, can present as masses behind the earlobe. Early detection is key for successful treatment.
• Rare Diagnoses
  • Branchial cleft cyst: These congenital anomalies can present as masses in the neck, including behind the ear. They are usually diagnosed in childhood but can occasionally be found in adults.
  • Metastatic disease: Rarely, a mass behind the ear could be a metastasis from a distant primary cancer. This would be an unusual presentation and typically associated with known primary malignancy or other systemic symptoms.