Primary Malignant Peripheral Nerve Sheath Tumors of Bone: A Clinicopathologic Reappraisal of 8 Cases

: Primary spindle cell and pleomorphic sarcomas of bone represent an exceedingly rare group of mesenchymal malignancies that include "soft tissue" histotypes, as malignant peripheral nerve sheath tumour. Outside the head and neck region, only 36 cases of primary malignant peripheral nerve sheath tumour of bone have been described. We retrieved from our archives eight cases of primary malignant peripheral nerve sheath tumour of bone arising outside the head and neck region, describing their clinical, radiological, and morphologic features. Our series, in which all but one patient died of diseases after a median of seven months, confirms that primary malignant peripheral nerve sheath tumours of bone are aggressive tumours. Pathologists should be aware of this rare histotype. More aggressive and active adjuvant treatments should be investigated.