Malignant peripheral nerve sheath tumours--report of 8 cases and review of the literature

Abstract

Background: Though Malignant peripheral nerve sheath tumours (MPNST) are a rare entity accounting for 5-10% of soft-tissue sarcomas they are an important differential diagnosis to benign tumours of the peripheral nervous system regarding treatment and prognosis.

Method: We present our experience with eight patients who underwent surgery for MPNST at the Department of Neurosurgery between 10/1990 and 9/1999. The median age was 37 years [range: 13-64], the male/female ratio was 1:1. Two patients suffered from Neurofibromatosis type 1. Paraffin embedded tumour specimens were immunohistochemically stained for S-100, p53 and Ki67/MIB-1.

Findings: The most frequent initial symptoms were local swelling and pain followed by irritation of cranial nerves and spinal ataxia. Four tumours were localised at the head & neck region, three were found in the extremities and one tumour was located on the trunk. All patients underwent surgery with curative intent, but total resection, defined by negative surgical margins, was achieved in only 3 cases. All of these developed local recurrence with a mean disease free survival time of 10.6 months. In five cases, adjuvant radiation was given. During follow up, three patients developed distant metastases located in the lung, liver and subcutaneous tissue. Five out of eight patients died during follow-up with a mean survival time of 11.6 months after diagnosis. Results of immunohistochemical staining were as followed: S-100 (7/8), p53 (7/8). The Ki67/MIB-1 proliferation index was detectable in all tumour samples, it differed from 10-30%.

Interpretation: MPNST is a rare and fatal diagnosis in neurosurgery with high risk of local recurrence and occurence of distant metastases. Though mulitimodal therapy including surgical resection and adjuvant radiotherapy including brachytherapy is available, the prognosis remains dismal. Modern clinical studies and the development of effective chemotherapy is needed in order to gain control of the disease.