Atlas of pathophysiology, 2 Edition

Part II - Disorders

Musculoskeletal disorders

Bone tumors

Primary malignant bone tumors (also called sarcomas of the bone and bone cancer) are rare, constituting less than 1% of all malignant tumors. Most bone tumors are secondary, caused by seeding from a primary site.

Age Alert

Primary malignant bone tumors are more common in males, especially in children and adolescents, although some types do occur in persons between ages 35 and 60.

Causes

Unknown

Suggested mechanisms

·   Rapid bone growth—children and young adults with primary bone tumors are much taller than average

·   Heredity

·   Trauma

·   Excessive radiotherapy

Pathophysiology

Bone tumors are growths of abnormal cells in bones. These abnormal cells divide uncontrollably and healthy tissue is replaced with unhealthy tissue. Bone tumors may originate in osseous or nonosseous tissue. Osseous bone tumors arise from the bony structure itself and include osteogenic sarcoma (the most common), parosteal osteogenic sarcoma, chondrosarcoma, and malignant giant cell tumor. Nonosseous tumors arise from hematopoietic, vascular, or neural tissues and include Ewing's sarcoma, fibrosarcoma, and chordoma.

Signs and symptoms

·   Bone pain (most common indication of primary malignant bone tumors); characteristics include:

§  greater intensity at night

§  usually associated with movement

§  dull and usually localized

§  may be referred from hip or spine and result in weakness or a limp.

·   Tender, swollen, possibly palpable mass

·   Pathologic fractures

·   Cachexia, fever, impaired mobility in later stages

Diagnostic test results

·   Incisional or aspiration biopsy confirms cell type.

·   Bone X-rays, radioisotope bone scan, and computed tomography scan reveal tumor size.

·   Blood studies reveal hypercalcemia and elevated alkaline phosphatase.

Treatment

·   Excision of tumor with a 3″ (7.6 cm) margin

·   Radiation therapy before or after surgery

·   Preoperative chemotherapy

·   Postoperative chemotherapy

·   Radical surgery, such as hemipelvectomy or interscapulothoracic amputation, if necessary (seldom)

·   Intensive chemotherapy

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TYPES OF BONE TUMORS

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