Malignant peripheral nerve sheath tumours in the head and neck region: retrospective analysis of clinicopathological features and treatment outcomes

Abstract

Malignant peripheral nerve sheath tumours (MPNST) are rare soft tissue sarcomas. The aim of this study was to assess clinicopathological characteristics and prognostic factors in order to improve the treatment of such tumours in the head and neck region. We performed a retrospective analysis of head and neck MPNST patients in our hospital between 1996 and 2012. Clinical features and pathological findings of these cases ( n = 43) were summarized. In addition, prognostic variables were evaluated by univariate and multivariate analyses. The median age of the patients at presentation was 41 years. Surgery was the main treatment approach. Pertinent information regarding the presence of neurofibromatosis type 1 was found in 13 patients (30.2%). Two-thirds of these patients were admitted for a primary tumour ( n = 27, 62.8%), while one-third ( n = 16, 37.2%) were treated for recurrent neoplasms. The overall survival rate was 46.5%. Multivariable analysis identified tumour size, surgical margins, and postoperative radiotherapy to be independent prognostic factors. MPNST of the head and neck is extremely difficult to manage. Surgery with postoperative radiation may be the optimum choice of treatment for primary head and neck MPNST.

Introduction

Malignant peripheral nerve sheath tumours (MPNST) constitute a rare group of malignant mesenchymal neoplasms that are commonly believed to arise from peripheral nerves, or to show differentiation of nerve sheath elements, including Schwann cells, fibroblasts, and perineural cells. They account for 3–10% of all soft tissue sarcomas. The estimated incidence of MPNST is claimed to be 0.001%. A certain correlation has recently been revealed between MPNST patients and those with neurofibromatosis type 1 (NF-1), which is also known as von Recklinghausen’s neurofibromatosis. Approximately 50% of MPNST of the extremities and trunk are derived from the malignant transformation of pre-existing neurofibromas, particularly in NF-1 patients with the distinctive features of café-au-lait spots, intertriginous freckling, Lisch nodules, or dermal and plexiform neurofibromas. Patients with hereditary NF-1 have an 8–13% lifetime risk of developing MPNST, and such diagnoses have usually been given at a relatively young age. Apart from this predilection, MPNST may also occur de novo, or as an uncommon and subsequent event to radiation therapy. Recent studies have suggested that the development of MPNST is a multistage process that may involve a number of altered cell cycle regulators. However, despite all the relevant research to date, the mechanism responsible for the malignant transformation remains poorly understood because of its rarity and aggressiveness.

MPNSTs tend to behave aggressively, with a high rate of recurrence and a propensity to metastasize hematogenously. Like other soft tissue sarcomas, wide surgical resection represents the mainstay of treatment; the role of adjuvant treatment is as yet unclear. Despite multimodality approaches, the prognosis of MPNST patients is generally dismal. The reported 5-year survival rate for patients with sporadic MPNST is around 50%, while this drops to as low as 10% for patients with NF-1.

MPNSTs are more likely to occur in the extremities than in the head and neck area. According to some, head and neck MPNST comprise only about 15% of all MPNSTs reported to date. Although a few reports of MPNST in the head and neck region have been published recently, including MPNST involving the tongue, cheek, mandible, parapharyngeal space, infratemporal fossa, and neck, studies with large series of cases are currently rare for this specific anatomical location and little information is available on the clinicopathological features, management options, and treatment outcomes of such disease. To contribute additional knowledge, we reviewed the cases of 43 patients seen in two departments of a single institution.

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Jan 19, 2018 | Posted by in Oral and Maxillofacial Surgery | Comments Off on Malignant peripheral nerve sheath tumours in the head and neck region: retrospective analysis of clinicopathological features and treatment outcomes
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