The Histology of Spontaneous Bone Tumours in Mice

Abstract

The gross pathology of bone tumours occurring spontaneously in an inbred strain of mice has already been described (4). In general, these appear to represent almost every possible phase of proliferative activity of the osteoblast; they may occur in any bone, and several or even all the bones in an animal may be affected. It is no exaggeration to say that every type of histologic change may occasionally be illustrated from a single mouse. The tumours from the first 106 sarcoma mice observed have been reexamined in an attempt to classify them according to the predominating type of cell. A number of these animals had multiple lesions of different types. Mouse 1688, for example, had a spindle-celled tumour of the tibia and an ossifying tumour involving the spine and ribs. Bone and osteoid tissue were the main features of tumours of the spine, ilium, and right femur of mouse 2706, which also had almost pure spindle-celled tumours of the rib and left femur. Mouse 2810 had a giant-celled tumour of the tibia and an osteoma of the spine. A number of similar examples might be quoted from the records. Of the 118 tumours, 89 consisted principally of bone and osteoid tissue; 20 were predominantly spindle-celled growths; 5 were mainly giant-celled tumours; and in only one was cartilage the principal feature, although it was present in 5 tumours of other types. There were two tumours in which spindle cells and osteoid tissue were present in equal amounts, and these must be classed as mixed tumours (one of these also contained cartilage), while one tumour was mainly round-celled, with some osteoid tissue and cartilage in addition. Giant cells were seen in 22 tumours altogether, and in only 10 tumours were there no signs of osteogenesis. The accompanying illustrations show the main types of tissue encountered.