Differential Diagnosis for an 11-Year-Old Man with a Level 2 Neck Mass
Single most likely diagnosis:
- Deep lobe Parotid adenocarcinoma: This is considered the most likely diagnosis because it is known to medialize the tonsil due to its location and growth pattern. The presentation of facial palsy (indicating involvement of the facial nerve) and the absence of cervical lymphadenopathy also support this diagnosis, as deep lobe parotid tumors can grow silently and cause significant local destruction before spreading to lymph nodes.
Other Likely diagnoses:
- Nasopharyngeal Carcinoma (NPC): Although less likely given the specific pattern of medialized tonsil and slight fullness of the post-nasal space without significant cervical lymphadenopathy, NPC can present with cranial nerve palsies, including CN XII palsy, due to its location and potential for local invasion.
- Jugular paraganglioma: This tumor can cause facial palsy and CN XII palsy due to its location in the jugular foramen. However, it typically presents with pulsatile tinnitus, hearing loss, and other symptoms related to its location at the skull base.
Do Not Miss diagnoses:
- Malignant change of vagal schwannoma: Although rare, schwannomas of the vagus nerve can undergo malignant transformation. Given the potential for significant morbidity and mortality with delayed diagnosis, it's crucial not to miss this possibility, especially with the presentation of cranial nerve palsies.
Rare diagnoses:
- Other rare tumors or conditions that could potentially cause this clinical presentation, such as metastatic disease to the neck from an unknown primary, primary lymphoma of the parotid gland, or other less common salivary gland malignancies. These would be considered based on further diagnostic workup and imaging findings.