Head and Neck Schwannomas: 20-Year Experience of a Single Institution Excluding Cutaneous and Acoustic Sites

Abstract

While head and neck sites comprise the most common location of schwannomas, clinicopathologic data regarding those tumors occurring in non-acoustic and non-cutaneous locations are relatively sparse. In this study, therefore, we sought to examine retrospectively the clinical and pathologic features of head and neck schwannomas excised at our institution over a 20-year period. During this period, we identified a total cohort of 85 patients, which included 36 males (42.4 %) and 49 females with average age of 41.3 years, the majority of which presented asymptomatically with a mass. Localized symptoms were, however, associated with all of the schwannomas that arose in the oral cavity and larynx, while tumors within or adjacent to bone were often associated with neurologic complaints (7 of 15 such tumors [46.7 %]). Clinical follow-up data was available in 86.4 % of all cases and demonstrated no recurrences or mortality. Pathologically, the microscopic features were characteristic of those well-described for schwannomas in other sites, including alternating Antoni A and B areas and the presence of degenerative changes. Tumor encapsulation, however, was variable and was completely absent in schwannomas of the nasal cavity, paranasal sinuses, and larynx. Additionally, a significant minority of the tumors (28.2 %) exhibited foci that resembled neurofibroma. Non-acoustic, non-cutaneous schwannomas of the head and neck appear to have clinicopathologic features similar to their soft tissue counterparts with some subsite variation in presentation and/or microscopic features.

Schwannoma of the tongue

“…Although schwannomas are generally encapsulated, this was not always the case in their study. Tumours arising from the nasal cavity, paranasal sinuses and larynx lacked a capsule 2. On histopathological examination, schwannoma is characterised by two patterns of tissue growth.…”

“…Schwannoma is a benign, most commonly encapsulated nerve sheath tumour 1 2. The neoplasm can occur alone3 or is a part of genetically inherited diseases such as neurofibromatosis type 1 (NF1), NF type 2 (NF2) and schwannomatosis 4 5.…”

“…NF2 gene functions as a tumour suppressor and a regulator of Schwann cells 4 6 7. Precise prevalence figures are not known 2 8. The tumour can affect the peripheral, cranial and autonomic nerves 9.…”

Encapsulated Sinonasal Schwannoma

“…Although the true incidence is unknown, in a study at one of the largest medical centers in the United States, only 85 schwannomas were diagnosed over a 20-year period at all head and neck sites (excluding skin and the acoustic nerve). 1 Schwannomas may occur in any myelinated nerve, with a predilection for the sympathetic trunk and cranial nerves. Most tumors arise in individuals between 40 and 60 years old with equal frequency in either sex.…”

Low CT Attenuation Values of Sinonasal Benign Tumours Relative to the Brainstem Identify Schwannomas

“…However, the clinical symptomatology of sinonasal schwannoma is non-specific [13] because the symptoms depend on the location or size of the tumour and the subsequent involvement of surrounding structures. The 4.…”