The periosteum may be the seat of a fibroma, a myxoma, or a lipoma. Chondromata also develop from the periosteum, are most common on the extremities, and are generally multiple. The osteomata are tumors formed of bone.

Sarcoma is the most frequent and the most important bone tumor, being also the only primary malignant growth. Any of the various forms may occur, the spindle-cell and the giant-cell being the most common, but round-cell, pigmented, and angiosarcoma are occasionally seen. The tumor may originate from the periosteum, the bone-marrow, or the bone. The giant-cell sarcoma, or epulis, is found upon the lower jaw, is usually only slightly malignant; may last for years and not give metastases. When the growth originates within the medulla, myeloid sarcoma, the bone gradually becomes much thinned and may break, allowing the tumor-cells to escape. An osteoid sarcoma is one generally arising from the periosteum at the ends of the long bones, and is characterized by the formation within it of irregular masses of bone.

Secondary infection may give rise to a general sarcomatosis of the bony structures.

Myeloma is the name given to a group of tumors that although resembling the sarcoma histologically, are derived from the special cells of the bone marrow and not from the periosteum. They are usually multiple and appear as grayish or reddish masses in the spongy bone. Microscopically there are three varieties of tumor according to the type of cell that predominates. Those composed of myelocytes; of red cells; and of plasma cells.

Chloroma is a form of sarcoma that is green or yellow in color, and is usually found in parts of the skull.

Carcinoma probably never occurs except as a secondary involvement, particularly in cases of carcinoma of the breast, thyroid gland, and prostate.