238 Theories and techniques of oral implantology

Fig. 6-47. In osteogenic sarcoma of the mandible, new bone trabeculae radiate from the normal peripheries of the jaw, producing a "sun ray" effect. (From Bhaskar, S. N.: Synopsis of oral pathology, ed. 3, St. Louis, 1969, The C. V. Mosby Co.)

Fig. 6-48. This chondrosarcoma in the maxillae is partially radiopaque. The enlargement has resulted in migration of the incisors, and neighboring roots have been partially re-sorbed by the lesion. (From Bhaskar, S. N.: Synopsis of oral pathology, ed. 3, St. Louis, 1969, The C. V. Mosby Co.)

Fig. 6-49. A reticulum cell sarcoma, shown here as a radiolucency in the maxillae, is usually painful. (From Bhaskar, S. N.: Synopsis of oral pathology, St. Louis, 1969, The C. V. Mosby Co.)

sive by the time the pain is felt. The mortality rate of osteogenic sarcoma is extremely high; less than 4% of patients survive. Death usually occurs within 1 year.

A chondrosarcoma may be either primary or secondary. A primary chondrosarcoma arises in a bone in a new form without any preexisting focus of cartilage. This cancer usually occurs during the first 20 years of life and is highly malignant. A secondary cartilaginous chondrosarcoma occurs as a malignant transformation of a previously benign chondroma. It is usually found only in older people and metastasizes slowly.

Fortunately, a chondrosarcoma is rare in the jaws (Fig. 6-48). If it does occur there it is dangerous because it may quickly extend along the neck to the mediastinurn or along the skull into the base of the brain. If the precancerous or cancerous condition is treated early and adequately, there is a good chance for cure.

Ewing's sarcoma, or Ewing's tumor, involves al-most any part of the skeleton of children and young adults under the age of 20. It often attacks the shafts of the long bones, rather than the ends, as is the case with osteogenic sarcoma. It is extremely rare in the jaws. Ewing's sarcoma is a lytic type of lesion, with the concentric layers of new bone giving a characteristic onion-skin appearance on x-ray examination. It is usually malignant, and survival is rare.

Reticulum cell sarcoma closely resembles Ewing's sarcoma grossly, radiographically, and histologically, but there are some differences that make it essential to distinguish between the two. Patients with reticulum cell sarcomas have a much better chance of survival, and treatment should not be delayed. Treatment includes radiation therapy or amputation.

When a reticulum cell sarcoma occurs in the oral regions, it may involve either or both soft tissues and bone. Although it occurs in the maxilla (Fig. 6-49), it is more common in the mandible. Jaw lesions apparently respond well to treatment. However good the response, implantation should be delayed for a long time to avoid complications resulting from recurrence.

Although giant cell tumor is usually benign, it can become malignant. When it does become malignant, it grows rapidly and destroys the cortex of the bone. Repeated curettage may not stop its recurrence.

Myeloma is a progressive, fatal disease that usually occurs after the age of 40, and mostly in men. Any bone may be affected, but the most common