Osteomata may be surrounded by a layer of fibrous periosteum or, in certain cases, beneath the periosteum appears a layer of cartilage producing the so-called exostosis cartilaginea. The latter formation is the one which is most common in the vicinity of the epiphyseal line of the long bones, notably of the leg.
Osteomata form circumscribed hard nodular masses of bony consistency, and are usually painless. They may cause interference with function from their size, especially when they appear in close connection with a joint.
Treatment is complete and thorough removal.
Sarcomata are the most common tumors of bone; they are malignant, and when removed, tend to recur, either locally or by metastasis, in different parts of the body. The metastases usually are distributed by the circulation.
These tumors may arise from the marrow, but generally in the epiphysis of the bone and extend to the shaft only at a later stage of their development. As the tumor advances, it causes a softening and an absorption of the original cellular marrow until it approaches the periosteum.
In many cases the periosteum, as about any form of foreign body, then begins to proliferate and forms a shell of periosteal bone surrounding the tumor. In that way the shell of the bone oftentimes becomes very much enlarged before there is any extension of the process through the shell to the adjacent tissue. By destruction of the marrow and of the cortex, great softening of the bone may occur so that spontaneous fractures not infrequently are seen.
Other sarcomata arise from the periosteum, and usually originate from one side of the bone, although occasionally they entirely surround the bone. In the periosteal sarcomata, a new formation of bone is common and the bone is frequently arranged in a radical way, giving a most remarkable picture on the X-ray plate.
Myeloma is a very rare malignant tumor of bone. Such tumors always appear only in connection with bone, are usually multiple, and are of the same type as other lymphoid tumors.
The cells of such tumors resemble very closely the type of plasma cell. These cells are arranged in masses without an intercellular substance, and the tumors are closely allied to the malignant lymphomata. The cases are always associated with albuminuria.
Symptoms. The chief symptoms of malignant tumors are swelling and pain, both of which oftentimes are extreme. The swelling may be spherical or spindle shaped.