Malignant triton tumour of the thigh—A retrospective analysis of nine cases

Malignant triton tumour (MTT) is a very rare soft tissue tumour. Aim To report nine patients diagnosed with malignant triton tumour of the thigh between January 1996 and January 2005 to determine the natural history and factors that may affect survival in this aggressive tumour. Methods Due to the association of Neurofibromatosis (NF Type I) with malignant triton tumour, two groups of patients were identified: those with NF type I (Group I cases); and those without (Group II). Results Group I patients accounted for four cases and arose predominantly in young males, all tumours being high grade, >10 cm in size and all four patients died within two years of diagnosis. By contrast, the five patients of Group II were older, had smaller size and lower grade tumours and three patients are long-term survivors. Conclusion Although the number of cases is small, our data supports the views that the natural history of MTT is more aggressive in patients with NF type I. This poor outlook could be attributed to the high frequency of Grade III histology in this disease and the large tumour size.