Hybrid Neurofibroma/Schwannoma of the Oral Cavity: A Rare Case Report and Literature Review

Abstract

Hybrid peripheral nerve sheath tumors show combined features of more than one type of conventional benign peripheral nerve sheath tumors. There are few cases reported of hybrid peripheral nerve sheath tumors in the head and neck region. A 68-year-old female patient was referred for evaluation of an oral swelling lasting five years. Intraoral examination revealed a small mobile nodule located in the lower vestibule. The patient underwent excisional biopsy and microscopic evaluation showed typical features of neurofibroma enclosing areas with palisading nuclei compatible with Antoni A pattern, which are seen in schwannomas. These regions showed strong and diffuse immunoreactivity for S100 protein and moderate positivity in the neurofibroma area. CD34 was positive in the neurofibroma area and entrapped axons were positive for neurofilament. The final diagnosis was oral hybrid neurofibroma-schwannoma tumor. Hybrid peripheral nerve sheath tumors, although extremely rare, may arise within the oral cavity. To the best of our knowledge, this is the first neurofibroma-schwannoma tumor reported in the oral cavity. Recognizing hybrid peripheral nerve sheath tumors as a distinct clinicopathological entity is important because they may also be associated with syndromic disorders.

Letter to Editor Regarding “Hybrid Neurofibroma/Schwannoma of the Oral Cavity: A Rare Case Report and Literature Review” by Leite et al

“…Recognition of hybrid neural lesions is important, as some may be associated with syndromes, especially neurofibromatosis types 1 and 2 and the patient may have multiple lesions. 2 In our case, the clinical investigation did not reveal other findings that could indicate a syndromic condition of the patient.…”

“…1 About 17 patients with this type of tumor located in the head and neck region have been described in the literature, and most was neurofibroma-schwannoma type. 2 Kazakov et al 3 (2005) reported two hybrid neurofibromaperineurioma tumors in the skin of the mammary and scapular region, whose diagnosis was established because they observed a biphasic pattern with two components, which resembled or were morphologically and immunohistochemically identical to a neurofibroma or perineurioma. 3 Despite the fact that some neurofibromas have a subpopulation of perineural cells, 4 in the present case, we saw clearly two distinct areas that morphologically resembled a perineurioma and a neurofibroma.…”

“…1 About 17 patients with this type of tumor located in the head and neck region have been described in the literature, and most was neurofibroma-schwannoma type. 2…”

The Occurrence of a Rare Mandibular Retromolar Triangle Schwannoma and Its Differentiation from Other Rare and Atypical Oral Cavity Tumours

“…In those cases, MRI imaging should always be performed to avoid any unnecessary treatment complications [29][30][31][32]. In the literature, only one hybrid ONT tumour type, namely, a neurofibroma-schwannoma tumour, was reported by Leite et al [33]. Surgical removal is the treatment of choice for each patient; however, multiple SCs or even solitary SCs can be associated with some syndromic disorders; therefore, a detailed patient anamnesis is important [25][26][27][28][29][30][31][32][33].…”

“…In the literature, only one hybrid ONT tumour type, namely, a neurofibroma-schwannoma tumour, was reported by Leite et al [33]. Surgical removal is the treatment of choice for each patient; however, multiple SCs or even solitary SCs can be associated with some syndromic disorders; therefore, a detailed patient anamnesis is important [25][26][27][28][29][30][31][32][33]. Each site of the oral cavity might be associated with a schwannoma.…”