Divergent differentiation in small round-cell tumours of the soft tissues with neural features--an analysis of 10 cases.

A series of 10 small round-cell tumours, having in common evidence of neural differentiation, were investigated by immunohistochemistry and electronmicroscopy. In seven, evidence of divergent muscle and/or epithelial differentiation was found. This phenomenon thus appears more common than previously appreciated and suggests that there may be a continuous and overlapping phenotypic spectrum from Ewing's tumour of soft tissue to intra-abdominal desmoplastic small cell tumour.