Differential Diagnosis for the Mass Under the Earlobe

The following differential diagnosis is based on the provided symptoms and characteristics of the mass.

• Single most likely diagnosis:

  • Calcified lymph node: The description of the mass as rock or bone hard, fixed, non-movable, and painless, along with its smooth and ball-like shape, could suggest a calcified lymph node. The location under the earlobe and the fact that it has been present for over a year without significant change also support this possibility.

• Other Likely diagnoses:

  • Salivary gland stone (sialolithiasis): Although the mass is described as being under the earlobe, it could be related to the parotid gland, which is located nearby. The hardness and fixed nature could be consistent with a stone, especially if it's causing a localized reaction.
  • Benign bone or cartilage tumor: Tumors such as an osteoma (bone tumor) or a chondroma (cartilage tumor) could present as hard, fixed masses. Their growth rate can be slow, which aligns with the minimal change over time described.
  • Lipoma or other soft tissue tumors: Although the mass is described as hard, some soft tissue tumors can feel firm or hard, especially if they are deep-seated. The fact that it's less palpable with certain movements could suggest it's embedded within soft tissues.

• Do Not Miss diagnoses:

  • Malignant tumor (e.g., metastasis or primary parotid gland tumor): Although less likely given the long duration and lack of significant growth, it's crucial not to miss a potential malignancy. Some tumors can grow slowly and may not cause pain or significant symptoms early on.
  • Parotid gland malignancy: Given the location, a malignancy of the parotid gland, although rare, must be considered. These can sometimes present as hard, fixed masses.

• Rare diagnoses:

  • Eagle syndrome: This condition involves an elongated styloid process or calcified stylohyoid ligament, which can cause a palpable mass in the neck, sometimes with pain. However, the painless nature and specific location under the earlobe make this less likely.
  • Branchial cleft cyst: These are congenital anomalies that can present as masses in the neck. They are usually softer and can become infected, leading to pain and swelling, which doesn't match the description provided.