HUMERUS - Probable Ewing's tumour

In the mid area of the shaft of the humerus in a young person there is a nodular tumour extending through the periosteum into the adjacent muscle. There are areas of pigment in the tumour which are not satisfactorily explained. This is a very old specimen and the colour may be misleading. The histology of the lesion is that of a small-celled tumour consistent with the diagnosis of Ewing's sarcoma.