{'fraction_non_alphanumeric': 0.031988873435326845, 'fraction_numerical': 0.02920723226703755, 'mean_word_length': 5.02092050209205, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 1, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 1, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
Malignant peripheral nerve sheath tumours associated with von Recklinghausen's neurofibromatosis.

AIMS
A retrospective study was conducted of patients with von Recklinghausen's neurofibromatosis who developed malignant peripheral nerve sheath tumours to determine their clinical characteristics, treatment outcome and prognostic factors.


METHODS
During the period 1987-1995, 29 patients with von Recklinghausen's neurofibromatosis (VRN) were seen at the Royal Marsden Hospital, of whom 23 had malignant peripheral nerve sheath tumours (MPNSTs).


RESULTS
The median age of the patients with MPNSTs was 30 years and the sex distribution was equal. The commonest site was the lower extremity, with a tendency for tumours to occur in the proximal parts. A nerve of origin was identified in 59% of the tumours and heterologous differentiation was present in 26%. Multiple primary MPNSTs occurred in four patients (17%) and other malignant tumours developed in three (13%). The overall 5-year survival was 35% with a median survival of 36 months. The incidence of local recurrence was 38% and 75% of them occurred within 2 years.


CONCLUSIONS
MPNSTs which develop in association with VRN occur in a younger age group, tend to be of a higher histological grade and are associated with a very poor prognosis. Tumour size > or = 10 cm (P=0.003) and high tumour grade (P=0.003) were adverse independent prognostic factors for overall survival.