Diagnosis: Laryngeal schwannoma
Schwannomas, which arise from neural crest–derived Schwann cells, account for 5% of all benign soft-tissue tumors; they can originate in any sympathetic, peripheral, or cranial nerve except the olfactory and optic nerves, which lack Schwann cells. Most schwannomas are sporadic, and there is a high incidence of schwannomas in patients with type 2 neurofibromatosis. Schwannomas can be differentiated from neurofibromas because the latter have a higher potential of recurrence and malignancy. Differentiation is also important because evidence of a neurofibroma should lead the clinician to the exclusion of a neurofibromatosis. The presence of a capsule, S-100 protein positivity, and the presence of Antoni A and Antoni B areas differentiate a schwannoma from a neurofibroma, which has a mixture of cell types. The single most common location for a schwannoma is the vestibular component of the eighth cranial nerve within the internal acoustic canal. The parapharyngeal space is the most common extracranial site. Schwannomas in the neck can arise from spinal or cranial nerve roots. Most tumors arise from the glossopharyngeal, vagus, accessory, and hypoglossal nerves.
Radiology Quiz Case 2: Diagnosis. Arch Otolaryngol Head Neck Surg. 2010;136(6):633. doi:10.1001/archoto.2010.77-b