Bone oncology is the most complex section of orthopedics due to the relative rarity of bone tumors, their pronounced polymorphism, presence of transitional forms, and absence of strictly specific clinical signs. Therefore, there is a high probability of diagnostic, and consequently, tactical errors. The dramatic nature of the situation is emphasized by the fact that primary bone tumors predominantly affect children and young people. In older age groups, metastatic bone lesions predominate with 10:1 ratio to primary tumors.
Classification
The clinical classification of bone tumors is complex and is constantly being transformed due to the identification of new neoplasm forms. A brief working classification of bone tumors proposed by S.T. Zatsepin is the most acceptable for clinicians (Table 22.1).
Table 22.1. Classification of bone tumors by S.T. Zatsepin
| Benign forms | Transitional forms | Malignant forms |
| Cartilage tissue tumors |
| Chondroma | - | Chondrosarcoma |
| Chondroblastoma | Mixed forms (with chondromyxoid fibroma, giant cell tumor) | Primary malignant chondroblastoma |
| Chondromixoid fibroma | Multifocal form with active growth | Malignant chondromixoid fibroma |
| Bone tissue tumors |
| Osteoma | Intraosseous well differentiated osteogenic sarcoma | Osteogenic sarcoma |
| Benign osteochondroma | Transitional forms | Periosteal sarcoma |
| Osteoid osteoma | Progressive osteoblastoma | Malignant osteoblastoma |
| Tumors of an undetermined origin |
| Giant cell tumor, osteoblastoclastoma | Transitional forms | Malignant giant cell tumor |
Table 22.1, continued
| Benign forms | Transitional forms | Malignant forms |
| Tumors of various connective tissue types |
| - | Chordoma | Malignant chordoma. Locally recurrent, metastatic |
| Benign fibrous histocytoma | Adamantinoma | Malignant fibrous histocytoma |
| Bone fibroma | Multifocal form | Bone fibrosarcoma |
| Bone lipoma | Various forms of lipomas | Liposarcoma |
| Vascular tissue tumors |
| Angioma. Capillary hemangioma. Venous angioma | Hemangioendothelioma. Hemangiopericytoma | Angiosarcoma and its variations |
| Tumors of the reticular bone marrow stroma |
| - | - | Ewing's sarcoma. Malignant lymphoma. Myeloma. Neuroectodermal tumor |
| Nervous tissue tumors |
| Neurofibroma | - | Malignant neurofibroma |
| Neurilemmoma | - | Malignant neurilemmoma |
| Tumors of joint capsules, tendon sheaths, synovial bursae |
| Benign synovioma | - | Malignant synovioma |
Diagnosis
Clinical presentation is scanty. Bone tumors may reach large sizes with almost no clinical manifestations. Often, patients accidentally discover a tumor, sometimes after a slight injury of the subcutaneous area. Pain is possible but not mandatory - at night and during exercise.
Visually and with palpation, it is not always possible to detect a tumor. Pain during palpation may be of varying intensity or absent. If tumor has destroyed the cortical bone, palpation may be accompanied by crepitation (this symptom is possible for a giant cell tumor). Ewing sarcoma is accompanied by hyperemia and swelling of tissues, an increase in body temperature, i.e., symptoms characteristic of osteomyelitis. The symptom of intoxication is not typical for bone tumors.
In case of para-articular localization of the tumor, restriction of motion range in the joint, lameness, muscle hypotrophy are possible.
With significant bone destruction, there is a risk of a pathological fracture. The fracture occurs as a result of a minor traumatic force, or even with a normal physiological load. Soreness in a pathological fracture is less pronounced than in a healthy bone fracture of the same localization.
Localization of the tumor in the spine or near the neurovascular bundle is dangerous due to possible compression of the spinal cord, its roots, peripheral nerves and large vessels. In such a situation, the leading clinical signs are spinal cord dysfunction, spastic and flaccid paresis or paralysis, signs of central or venous blood flow disorders.
Instrumental examination
Radiological diagnostics allows not only to clarify the diagnosis but also sometimes to identify a tumor at random for the first time due to the scarcity of clinical manifestations. X-ray in two standard views allows a significant number of observations to obtain information about the presence, localization, and volume of the tumor. In questionable cases, the examination program of patients includes all possible modern diagnostic methods (X-ray tomography, CT, MRI, scintigraphy, etc.).
Puncture or surgical biopsy is used to clarify the nature of the tumor. However, the data of histological examinations are often erroneous due to the polymorphism of bone tumors, the presence of mixed forms. Therefore, selection of treatment is a difficult task for a clinician.
General treatment principles
Surgical methods of treatment prevail in bone oncology. The development and implementation of modern technologies (endoprosthetics, microsurgical techniques, use of bone-substituting materials) allow to avoid amputation and perform organ preservation surgery in most cases even with malignant tumors.
The following surgeries are performed:
- tumor enucleation;
- bone resection with defect replacement;
- endoprosthetics of bones and joints.