MPNST accounts for 5% of all sarcomas. 50% of cases are associate with von Recklinghausen's disease. Two thirds of MPNST arise from neurofibromas, one third arise de novo. Origin from a pre-existing Schwannoma, ganglioneuroma or phaeochromocytoma is rare.
Histopathology
MPNST is composed of spindle cells forming fascicles. Nuclei are tapered. Cellularity is variable, with perivascular accentuation. Heterologous elements (epithelial, rhabdomyoblastic, chondroid, osteoblastic or angiosarcomatous) are present in about 15% of cases.
Immunohistochemistry
|
50-90% (typically only one third of neoplastic cells are immunoreactive)1 |
|
|
50% |
|
|
40% |
|
|
0/163 |
|
|
0/83 |
|
|
0/373 |
|
|
6/133 |
|
|
0/133 |
|
|
4/423 |
|
|
0/83 |
|
MPNSTs associated with neurofibromatosis-I show evidence of diverse differentiation1:
|
13/231 |
|
|
13/201 |
|
|
15/201 |
|
|
4/191 |
|
|
6/201 |
|
|
6/221 |
|
|
3/221 |
|
|
3/201 |
|
|
5/221 |
|
|
9/191 |
|
S-100 immunoreactivity is indicative of Schwannian differentiation, EMA+/collagen IV+/NGFR+//S-100- indicates perineural differentiation, CD34 positivity may be associated with known perivascular fibroblast-like cells. Some cases variously shows morphological and ultrastructural evidence of rhabdomyoblastic2 and cartilaginous differentiation.
Prognosis
MPNST is an aggressive tumour with a five-year survival of 35%.
References
1Histopathology 2001;39:298-309.
3Chu, P. G. and L. M. Weiss (2002). "Keratin expression in human tissues and neoplasms." Histopathology 40(5): 403-39. (Summary data from multiple papers)
This page last revised 4.1.2004.
©SMUHT/PW Bishop