© Springer-Verlag London 2016
Dominique G. Poitout (ed.)Biomechanics and Biomaterials in Orthopedics10.1007/978-1-84882-664-9_3030. Malignant Bone Tumors: From Ewing’s Sarcoma to Osteosarcoma
(1)
Faculté de Médecine Nord, Sce Chirurgie Orthopédique et Traumatologie, Aix-Marseille Université, Centre Hospitalier et Universitaire Marseille North, Chemin des Bourrely, 13015 Marseille, France
(2)
Aix-Marseille Université, Centre Hospitalo-Universitaire Marseille Nord, Marseille, France
Introduction
Primitive malignant bone tumors are rare as they represent less than 1 % of all cancers. Osteosarcoma and Ewing’s sarcoma occur the most frequently. They affect, in particular, older children, adolescents, and young adults. For many years these tumors could be controlled locally (often involving an amputation) by radical surgery accompanied or not by radiotherapy, depending on the histological type. Unfortunately, most of the patients died within 2 years from secondary lesions in the lung.
Only recently has it been possible to improve the survival rate. Indeed, the prognosis of these tumors, until then complicated by the occurrence of pulmonary metastases in almost 90 % of cases, has been revolutionized by the advent of “heavy” chemotherapies, capable of eradicating infraclinical metastases. At the same time, the progress made in surgical techniques has enabled the number of limbs saved to be increased and therefore an improvement in the future of these young patients in terms of function. First of all we should stress the importance of close multidisciplinary collaboration, from diagnosis to post-therapeutic monitoring through all the stages of treatment, a collaboration upon which the prognosis of the survival of the patient for whom we are responsible depends.
Epidemiology
Frequency
There are approximately 100 new cases of osteosarcoma per year in France. The incidence of Ewing’s sarcoma is estimated at two to three new cases per year and per million children under 15 years of age in the USA and in the United Kingdom. There is a slight preponderance of males suffering from these two tumors with a gender ratio of approximately 1:5. Osteosarcoma can occur at any age but is found mainly in young people with an average age of 17 years.
Ewing’s sarcoma most often occurs during the second decade of life with an average age of 11. It is exceptional before 5 years of age and after 30. Finally, it should be noted that Ewing’s sarcoma is very rare in people of black African descent.
Risk Factors
There is often a history of trauma in the weeks preceding the discovery of the tumor, but whether this factor is responsible is still being discussed and it could be no more than a factor which makes clinical discovery more likely. Both types of tumor seem to occur more frequently in tall patients. This, no doubt, is related to the hormone changes of rapid growth.
Osteosarcoma
In the child, osteosarcoma may be accompanied by familial retinoblastoma in 4 % of cases. Then the same cytogenetic anomalies are found for bone tumors as for the retinal tumors. One percent of Paget’s disease of the bone can degenerate into osteosarcoma. A radiation-induced etiology is also possible for this disease (osteosarcomas have been described in particular after anti-inflammatory radiotherapy for aneurysmal bone cysts). In these two latter cases, adults beyond the quarantine period are most often involved.
Tumors of the ethmoid in people exposed to wood dust are classical, with the most frequent histology being adenocarcinomas, of course, but osteosarcomas can also be present.
Ewing’s Sarcoma
Few specific risk factors have been described for Ewing’s sarcomas. They may occur on pre-existing benign bone lesions.
Pathological Anatomy
Varieties
Osteosarcomas
Osteosarcomas start in the center of the medulla, most frequently in the metaphysis of the long bones. The lower extremity of the femur, and the upper extremity of the tibia or of the humerus are the most frequent sites (80 % of cases). At a microscopic level, these tumors are characterized by osteoid production. Osteoblastic and chondroblastic varieties (characterized by the presence of chondroid tissue) have been described. Due to cell differentiation and the quality of the stroma, distinctions can be drawn between the fibrous osteosarcomas (with an abundance of collagen), telangectasic osteosarcomas (considerable vascularization), and anaplastic osteosarcomas (very non-differentiated). These last two varieties have the worst prognosis. Parosteal sarcoma, a highly ossifying variety of osteosarcoma, has a better prognosis.
Anatomical pathological examination can also pinpoint the fusiform or small cell nature of the tumor (the latter have a poorer prognosis). Some authors also suggest a cytological scale of 1–4 in order of increasing malignancy. Indeed, the introduction of intensive chemotherapy has removed the role of these prognostic factors. The histological variety of the tumor no longer affects the course of the disease.
Ewing’s Sarcoma
Unlike osteosarcoma, in more than half of cases, Ewing’s sarcoma develops in the axial skeleton starting from the pelvic girdle. This fact was first described by J. Ewing in 1921 as a bone tumor with small round cells, distinct from osteosarcoma. The origin of the tumor has long been discussed. An endothelial, neural, mesenchymatous starting point has been suggested. It would currently appear, owing to the immunohisto-chemical and cytogenetic data, that it is one of the tumors deriving from the neurectodermis, of which it would be the least differentiated form, and of which the neuroepithelioma would be the differentiated form.
From an anatomical pathological point of view, it is a monomorphous proliferation of small round cells with fine chromatin, positive PAS, with a fine network of intercellular reticulin. Immunohistochemistry and, in particular, cytogenetics make it possible to differentiate Ewing’s sarcoma from other small round cell tumors in the child and in the adolescent. In more than 80 % of cases of Ewing’s sarcoma, there is specific translocation (11, 22 q24; q12). In the absence of specific translocation, chromosome 22 derives from translocation in 9 % of cases.
Spread
Osteosarcomas
It is customary to say that “osteosarcoma is a lung disease starting in the bone”. This brief description straight away emphasizes the early and extreme frequency of the pulmonary micrometastases which do, of course, determine the prognosis in terms of survival. Locally, the tumor develops centrifugally, invading and destroying the normal bone up to the cortex and to the adjacent soft tissue. There is often a pseudo-capsule which really consists of inflammatory tissue at the interface between the tumor and normal tissue.
The very frequent presence of satellite tumoral nodules situated on the same bone as the main tumor but not continuous with it has also been described. These are, in fact, “local metastases” which have developed from tumoral emboli via the medullary sinuses. These have to be taken into account when determining the extent of the surgical excision. Ganglionic involvement is unusual for this histological type since it only appears in less than 10 % of cases in autopsy series. On the other hand, hematogenic metastases are extremely frequent and develop at an early stage. They occur predominantly in the lungs, and it is estimated that approximately three-quarters of patients have microscopic pulmonary metastases at the time of diagnosis.
The second site for metastases in order of frequency is the bone but it is rare that bone metastases are present if earlier pulmonary lesions are absent. Other types of metastases only occur very exceptionally.
Ewing’s Sarcoma
The local development of Ewing’s sarcoma is slightly different. There is often complete invasion of the medullary cavity of the bone concerned as well as involvement of the cortex and of the soft tissue. Ganglionic metastases seem to be a little more frequent than for osteosarcomas, but here, too, it is the hematogenous metastases which tend to occur with a frequency of 15–40 % at the time of diagnosis. Pulmonary secondaries still arrive there first, followed by bone metastases and invasion of the medulla.
Diagnosis
Circumstances in Which It Is Discovered
Pain is often the first symptom; it may be intense and accompanied by serious functional infirmity or, on the other hand, not intense and only felt if pressure is applied. Sometimes there is a nocturnal recrudescence. This pain, caused by intraosseous hypertension, is considerable in the forms which start centrally. It may also be accompanied by limping in lesions of the leg.
Its site varies depending on the type of tumor:
In the case of osteosarcoma, it is most frequently found in the metaphysis of the long bones, “close to the knee and far from the elbow”. Lower extremity of the femur (50 %), upper extremity of the tibia (15 %), upper extremity of the humerus (15 %).
Ewing’s sarcoma tends to develop in the axial skeleton and in shoulder and pelvic girdles. Involvement of the flat bones, although exceptional for osteosarcomas, is very common in Ewing’s sarcoma.
The tumor can also be palpated. A careful examination shows that it is one with the bone, with the neighboring joints rarely being affected. It varies in consistency, being hard, firm, or sometimes softer. The tumor may be pulsating. Classically there may be crepitus on pressure but this sign is, in fact, rare. The tumor increases rapidly in size, deforming the bone concerned; the skin has a smooth and stretched appearance, with dilated veins.Related posts:
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