Hybrid in the hypopharynx: Case report of a hybrid neurofibroma-schwannoma

Hybrid peripheral nerve sheath tumors (HPNSTs) are classified as benign peripheral nerve sheath tumors that consist of at least two tumor subtypes - neurofibroma, schwannoma, or perineurioma - at the lesion site. While there are reports of these lesions in the head and neck, there is no documentation of a hypopharynx hybrid neurofibroma-schwannoma in the literature. This case report describes the clinical presentation, treatment, and histopathologic features of a hypopharynx hybrid neurofibroma-schwannoma in a 45-year-old man. The patient presented to clinic with mild dysphagia and globus but no prior history of head and neck cancer. Flexible laryngoscopy revealed a large smooth nodular pedunculated mass stemming from the posterior pharyngeal wall obstructing the airway. The patient underwent microdirect suspension laryngoscopy biopsy and excision of the hypopharyngeal lesion. Pathology revealed a 3.5 cm combined nerve sheath tumor showing features of both neurofibroma and schwannoma. These tumors remain benign with no increased risk for recurrences, malignant transformation, or association with neurofibromatosis syndromes. The pathogenesis of HPNST lesions remains unclear and is even more uncertain in the hypopharynx. There is little data on the rate of malignancy given the extremely low incidence of these tumors. Regardless, these tumors represent clinically distinct pathologies which clinicians must be aware of in their differential diagnosis.