Treatment.—In view of the unstable quality of the chondroma, especially of its liability to become malignant, it should be removed as soon as it is recognised. In those projecting from the surface of a bone, both the tumour and its capsule should be removed. If in the interior, a sufficient amount of the cortex should be removed to allow of the tumour being scraped out, and care must be taken that no nodules of cartilage are left behind. In multiple chondromas of the hand, when the fingers are crippled and useless, exposure to the X-rays should be given a trial, and in extreme cases the question of amputation may have to be considered. When a cartilaginous tumour takes on active growth, it must be treated as malignant.
Fig. 51.—Chondroma of Metacarpal Bone of Thumb.
The chondromas that are met with at the ends of the long bones in children and young adults form a group by themselves. They are usually related to the epiphysial cartilage, and it was suggested by Virchow that they take origin from islands of cartilage which have not been used up in the process of ossification. They are believed to occur more frequently in those who have suffered from rickets. They have no malignant tendencies and tend to undergo ossification concurrently with the epiphysial cartilage from which they take origin, and constitute what are known as cartilaginous exostoses. These are sometimes met with in a multiple form, and may occur in several generations of the same family. They are considered in greater detail in the chapter dealing with tumours of bone.
Minute nodules of cartilage sometimes form in the synovial membrane of joints and lining of tendon sheaths and bursæ: they tend to become detached from the membrane and constitute loose bodies; they also undergo a variable amount of calcification and ossification, so as to be visible in skiagrams. They are further considered with loose bodies in joints.
Cartilaginous tumours in the parotid, submaxillary gland, and testicle belong to a class of “mixed tumours” that will be referred to later.
Osteoma.—The true osteoma is composed of bony tissue, and originates from the skeleton. Two varieties are recognised—the spongy or cancellous, and the ivory or compact. The spongy or cancellous osteoma is really an ossified chondroma, and is met with at the ends of the long bones ([Fig. 52]). From the fact that it projects from the surface of the bone it is often spoken of as an exostosis. It grows slowly, and rarely causes any discomfort unless it presses upon a nerve-trunk or upon a bursa which has developed over it. The Röntgen rays show a dark shadow corresponding to the ossified portion of the tumour, and continuous with that of the bone from which it is growing ([Fig. 138]). Operative interference is only indicated when the tumour is giving rise to inconvenience. It is then removed, its base or neck being divided by means of the chisel. The multiple variety of osteoma is considered with the diseases of bone.
The bony outgrowth from the terminal phalanx of the great toe—known as the subungual exostosis—is described and figured on [p. 404]. Bony projections or “spurs” sometimes occur on the under surface of the calcaneus, and, projecting downwards and forwards from the greater process, cause pain on putting the heel to the ground.