Parapharyngeal tumors are rare and often missed because of their subtle presentation. This is true for a 21-year-old woman who presented with a gradually progressive swelling in her mouth for 3 months associated with difficulty in swallowing.
Assessment
On oral examination, there was a smooth bulge in the left pharyngeal wall pushing the left tonsil medially (Figure 1). Her systemic and neurologic examination results were within normal limits. Radiologic evaluation revealed an enhancing, smooth, well-defined encapsulated lesion in the left parapharyngeal space (Figure 2).
Diagnosis
A provisional diagnosis of schwannoma of the parapharyngeal space was made. Parapharyngeal space tumors are rare and account for only 0.5% of all head and neck tumors. Schwannoma is the most common neural tumor next to salivary gland tumors found in the parapharyngeal space. Vagus nerve is reported to be the origin for 50% of parapharyngeal schwannomas. Schwannomas are characterized by slow and asymptomatic growth; however, their progressive growth in the parapharyngeal region may result in pressure effect manifestations, such as dysphagia and hoarseness of voice.
Management
Treatment is surgical excision transorally or through a neck incision. Prognosis is good, and recurrences are rare after excision. In our patient, the lesion was excised through an external neck incision. The postoperative biopsy showed characteristic hypocellular (Antony B) and hypercellular (Antony A) areas that were immunohistochemicaly positive for S-100, consistent with schwannoma (Figure 3). The patient is asymptomatic at 9 months of follow-up visits.
To read this article in its entirety please visit our website.
-Satvinder Singh Bakshi, MS, DNB
This article originally appeared in the December 2016 issue of The American Journal of Medicine.
