Tumors of the Bone
The prevalence of bone tumors in the United States is approximately 7 children per million under the age of 15 years. Although rare, with approximately 400 cases diagnosed per year, osteosarcoma is the most common primary malignancy of bone during the adolescent growth spurt (rapid bone growth) (309).
There is a slight preference for boys. It is followed by Ewing's sarcoma, with approximately 200 cases diagnosed per year. Ewing's sarcoma is more common in those younger than 10 years of age (372). However, both tumors present more commonly in the second decade of life. Osteosarcoma may develop from irradiation treatment of Ewing's or other malignancies. Tumors may mimic various pain syndromes throughout the body. Primary bone tumors common to the upper extremities include Ewing's sarcoma of the scapula, osteogenic sarcoma of the proximal humerus, and osteoblastomas and chondroblastomas common in the diaphyses and epiphyses of long bones (373). The most common presenting manifestations of osteosarcoma are pain, limp, and swelling. Similar presentation may be found in Ewing's, as well as weight loss and fever.Diagnostics. The timing of the presentation complicates the differential diagnosis. The symptoms may be attributed to a growth spurt, sprain, or sports injury. Those presenting with osteosarcoma are usually taller than their peers. A complaint of pain that awakens a child or adolescent from sleep is suggestive of malignancy. The most common location of the osteosarcoma is the distal femur, followed by the proximal tibia and proximal humerus. Symptoms not responding to conservative treatment require further investigation, specifically with a radiograph. A sunburst pattern or Codman’s triangle (lifting of the cortex by new bone formation) are classic radiographic findings found in two-thirds of those presenting with osteosarcoma. With Ewing’s, a permeative “moth-eaten appearance” is demonstrated on x-ray.
If suspicion of tumor is high, and radiograph is negative, seen with medullary osteogenic sarcoma, MRI should be obtained of the entire long bone, as no pattern on x-ray is pathognomonic (374). Laboratory tests, including a complete blood count (CBC), will usually be normal. Elevated sed rate, alkaline phosphatase, or lactic dehydrogenase levels may be found. Early diagnosis is key, as the prognosis is better if there is less spread of the disease. Metastasis to the lungs remains the most likely cause of death. Additional primary bone tumors to the lower extremities include those of the long bones. These include histiocytosis X in the diaphysis and esosinophilic granuloma in the epiphysis. Tumors more common in the area of the pelvis include osteoblastoma, aneurysmal bone cyst, and fibrous dysplasia. Additional metastatic tumors to the lower extremities include neuroblastoma and lymphomas of various types.Treatment. This requires wide resections of the long bone and adjuvant chemotherapy. Once diagnosed, further workup and treatment is necessary at a center with expertise in managing these tumors.
Rehabilitation. Physical activity and contracture management are important rehabilitation issues during acute treatment. Chronically, residual limb skin integrity, prosthesis management, and contracture management are important issues when managing this patient population. Team management is critical, led by the pediatric rehabilitation medicine specialist in the comprehensive care of patient, family, and loved ones.