A study of histological features distinguishing chordoma from chondrosarcoma

DURING THE COURSE OF THE WORK of the Cancer Research Campaign Bone Tumour Panel (Sweetnam et al., 1971) a large number of tumours in bone have been studied histologically, with the support of clinical and radiological information. Included amongst the more than 1200 tumours are 11 chordomas. One of these was a tumour from an unspecified part of the skull and facial skeleton from which a small but adequate biopsy sample had been obtained in 1961. The histological appearances of this showed a mixture of chordoid and chondroid tissues. Heffelfinger et al. (1973) had reported 22 cases of this type in 1973. Nevertheless one of the difficulties in accepting the reality of this state of affairs was uncertainty over the criteria for recognizing the two types of tissue, and the reliability with which the distinction could be made. This uncertainty led to the following analytical study. Each of the then 6 members of the Panel examined in turn a collection of sections stained with haematoxylin and eosin, one from each of 29 cases (Table I). The collection was known to contain chondrosarcomas, chordomas and other neoplasms, but no other information was provided. The observers were asked to indicate which of 4 diagnostic categories they felt was most suitable for each section, and to record the histological features used to recognize chordoma and chondrosarAecepte(d 21 October 1980