[Malignant triton tumor (immunomorphological research)].

Immunohistochemical study with the use of PAP method on paraffine sections of two cases of triton tumour one of which developed against the background of Recklinghausen disease. The presence of vimentin and S-100 protein in the neurofibromatous cells and spindle-cell component of malignant triton tumour is shown. The muscle differentiation markers (desmin and myoglobin) are found in the polymorph-cell component. The positive reaction of the cytoplasmic processes of some cells in the neurofibromatous tissue to the antibodies against GFAP (glial fibrillar acid protein) is discussed. It is suggested that the number of S-100 protein-positive and vimentine-positive cells in the peripheral nerve sheath tumours reflects the degree of their differentiation. Hypotheses of the histogenesis of these rare tumours are discussed. The panel of antibodies for the differential diagnosis of malignant triton tumour with rhabdomyosarcoma, malignant schwannoma and other soft tissue tumours is proposed.