The importance of surgical margins in malignant triton tumour of the trunk and extremities

Abstract

Malignant Triton tumour (MTT) is a rare variant of malignant peripheral nerve sheath tumour with partial rhabdo- myosarcomatous differentiation. To the best of our knowledge, the importance of the surgical resection margins on the outcome of patients with MTT is unknown. The present study is a retrospective review of 24 patients treated for MTT of the trunk and the extremities between 1997 and 2015 in two insti- tutions. The association of surgical margins with overall and tumour recurrence-free survival was analysed. Furthermore, the typical morphological and immunohistochemical char- acteristics of the tumour were described. In patients treated with curative intent (17/24), a surgical margin exceeding 1 mm was significantly associated with better overall survival and local recurrence-free survival. The oncological outcome was however poor, with only 28% of patients surviving at 5 years. Histopathologically, necrosis was a common feature, and most tumours displayed focal positivity for S100 protein and focal or strong positivity for desmin. The present results highlight the aggressive behaviour of MTTs and underline the impor- tance of adequate surgical treatment.