Differential Diagnosis for a Lump in the Left Posterior Neck
Single Most Likely Diagnosis
- Lymphadenopathy: This is the most common cause of a lump in the neck, and a 2 cm size is consistent with reactive or infectious lymphadenopathy. The location in the posterior neck and lack of mobility could suggest a reactive or infectious process.
Other Likely Diagnoses
- Lipoma: A benign tumor of fat cells, lipomas can occur in the neck and are often mobile, but a fixed lipoma is possible. The size of 2 cm is consistent with a lipoma.
- Cyst: A congenital or acquired cyst, such as a branchial cleft cyst, could present as a lump in the posterior neck. While mobility is variable, a cyst could be fixed if it is adherent to surrounding structures.
- Fibroma: A benign tumor of fibrous tissue, fibromas can occur in the neck and may be fixed or mobile.
Do Not Miss Diagnoses
- Metastatic Cancer: Although less likely, a lump in the neck could be a metastasis from a primary cancer, such as thyroid, lung, or head and neck cancer. The lack of mobility could suggest invasion into surrounding tissues.
- Tuberculosis: TB can cause lymphadenopathy in the neck, and the posterior location could suggest a tuberculous abscess. Although less common, TB is a critical diagnosis not to miss due to its public health implications and need for specific treatment.
- Sarcoma: A rare but aggressive tumor of soft tissue, sarcomas can occur in the neck and may present as a fixed mass.
Rare Diagnoses
- Carotid Body Tumor: A rare benign tumor of the carotid body, these tumors can occur in the neck and may be fixed due to their location near the carotid artery.
- Neurofibroma: A benign tumor of nerve tissue, neurofibromas can occur in the neck and may be fixed or mobile.
- Thyroglossal Duct Cyst: Although typically midline, a thyroglossal duct cyst could present off midline and in the posterior neck, especially if it is ectopic.