Malignant peripheral nerve sheath tumours (MPNST)

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

S-100

50-90%1

Leu-7

50%

MBP

40%

Cytokeratin 1

0/163

Cytokeratin 5/6

0/83

Cytokeratin 7

0/373

Cytokeratin 8/18

6/133

Cytokeratin 13

0/133

Cytokeratin 19

4/423

Cytokeratin 20

0/83

   

MPNSTs associated with neurofibromatosis-I show evidence of diverse differentiation1:

S-100

13/231

g-NSE

13/201

NGRF

15/201

NF

4/191

EMA

6/201

Cam5.2

6/221

desmin

3/221

SMA

3/201

CD34

5/221

collagen IV

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.

2Ordonez, N. G., Tornos, C. Malignant peripheral nerve sheath tumor of the pleura with epithelial and rhabdomyoblastic differentiation: report of a case clinically simulating mesothelioma. Am J Surg Pathol 1997;21:1515-1521.

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