Primary malignant peripheral nerve sheath tumour of the heart

Aims: Malignant peripheral nerve sheath tumour (MPNST) is an unusual sarcom a of the heart and should be differentiated from other spindle cell sarcoma s. Methods and results: We combined morphological, immunohistochemical and cytogenetic techniques in the differential diagnosis, particularly from mon ophasic synovial sarcoma. The tumour consisted of dense fascicles, alternat ing with hypocellular, myxoid zones. There was a marked herniation of tumou r cells into the vascular lumen. Immunohistochemically, the tumour cells ex pressed vimentin and focally S100 protein. There was no expression of cytok eratin or epithelial membrane antigen (EMA). Although we found a complex ka ryotype, the finding of involvement of 17q11, the loss of chromosome 22, an d the absence of a t(X;18)(p11.2;q11.2), which characterizes synovial sarco ma, allowed us to the final diagnosis of malignant peripheral nerve sheath tumour. Conclusion: MPNST of the heart can be diagnosed by combining morphological and immunohistochemical date. Cytogenetics can be useful in reaching a corr ect diagnosis, also by helping to rule out monophasic synovial sarcoma.