malignant peripheral nerve sheath tumor (MPNST)

usually malignant neurofibroma (neurofibroscarcoma), malignant schwannomas being extremely rare. Sarcomatous transformation, particularly of plexiform neurofibromas in neurofibromatosis type 1, can occur. Microscopic pathology: - anaplastic spindle cells - high cellularity - high mitotic activity - histologic subtypes 1) epitheliod MPNST 2) MPNST with epithelial or mesenchymal differentiation 3) melanotic MPNST Immunohistochemistry: - S100: +, less so than schwannoma - CD34: variable - leu 7: +

General

nerve sheath tumor soft tissue sarcoma (STS)

References

WHO International Histological Classification of Tumors. Histological Typing of Tumours of the Central Nervous System. Kleihues et al. Springer-Verlag 2nd ed. 1993