MALIGNANT PERIPHERAL-NERVE SHEATH TUMOR WITH VASCULAR DIFFERENTIATION- A REPORT OF 4 CASES

Four cases of malignant peripheral nerve sheath tumour showing vascula r differentiation are described. One case was associated with neurofib romatosis 1 and contained angiosarcomatous, cartilaginous and rhabdomy oblastic elements. The other cases occurred in patients without neurof ibromatosis and showed a spectrum of vascular lesions ranging from lob ulated, haemangioma-like structures to angiosarcoma. These are the fir st recorded examples of this phenomenon not associated with neurofibro matosis. Immunohistochemical examination demonstrated the endothelial nature of the lesions in all cases and revealed cells positive for alp ha-smooth muscle actin, probably pericytes, closely apposed to the end othelium.