wing of the sphenoid, but it could not be cut as easily as the maxilla. In addition to the maxilla, pieces of bone were removed for histological examination from the right sphenoid, temporal, and frontal bones. The striking feature of the malignant process was its apparent localization to bone.
Histology.-The appearances of the biopsy and post-mortem specimens are similar. In all of them there is invasion and destruction of bone by well-differentiated squamous carcinoma with cell-nest formation. Where the growth has invaded the bone there is a fibrous-tissue reaction and some new bone formation (Figs. 297, 298). Except in the maxilla the fibrous tissue is in excess of the carcinoma, but in none of the sections examined was fibrous-tissue replacement of bone found without carcinoma. The part of the antrum included in the section of maxilla has a normal columnar epithelial lining.
Comment.-On admission this was thought to be a case of leontiasis ossea. Carcinoma was not suspected until biopsy was performed. The site of origin of the carcinoma was not discovered, but was probably one of the tooth sockets of the upper jaw. Before the biopsy there was nothing in the mouth to suggest carcinoma, and at post-mortem the cavity of the antrum was not obliterated and its lining was found to be normal columnar epithelium. When the result of the biopsy was known there was still doubt as to the nature of the diffuse change seen in the radiographs. It was thought that there might be two conditions present, carcinoma and osteitis fibrosa, but no evidence of the latter was found post mortem. The unusual feature of the case is the local spread of carcinoma in the bones rather than in the soft tissues, which showed no macroscopic involvement at post-mortem.