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Fibrosarcoma
Soft Tissue
Fibrosarcoma is a malignant fibroblastic tumor characterized by interlacing bundles of collagen fibers. This sarcoma may occur in various soft tissues, as well as, in bone. In the past 40 years diagnostic criteria have been established to better define its pathological characteristics. At one time all highly cellular, collagen-forming spindle cell tumors were labeled as fibrosarcoma. Currently, with the recognition of entities such as: malignant fibrous histiocytoma, liposarcoma, rhabdomyosarcoma, leiomyosarcoma, malignant schwannoma and aggressive fibromatosis, the actual incidence of fibrosarcoma is dramatically less than originally thought. This change in criteria for diagnosis has made it difficult to determine the exact incidence of fibrosarcoma, but many recent large studies have indicated that it is one of the least common soft tissue. Fibrosarcoma may occur at any age, but it is most commonly seen in the 4th to 6th decades. A female predominance has been noted in many series, although others have not appreciated a significant difference. Fibrosarcomas develop spontaneously, and have no identifiable etiologic agent. The five-year survival reported has range from 41% to 70%. Survival and the incidence of metastasis are influenced by the tumor grade and adequacy of surgical margin. At one time radical resection was considered the only option for treating these aggressive soft tissue sarcomas. With the development of adjuvant chemotherapy and radiotherapy limb salvage is an option. Limb salvage reconstruction allows the patient to have a functional limb as well as have comparable five-year survival statistics to radical surgery. Fibrosarcoma is a rare soft tissue tumor with a high rate of pulmonary metastasis with a low five-year survival. The survival and incidence of metastasis is influenced by tumor grade and adequacy of surgical margins. Although clear margins had a direct favorable impact on limiting recurrence, survival and rate of metastasis occurrence was not affected. Even though the incidence of tumor recurrence was not found to be significantly less than in adults, those patients less than 5 years of age with a recurrence did not have an increase incidence of metastatic disease
Bone
Fibrosarcomas of bone are rare tumors compromising less than 5% of bone sarcomas. Fibrosarcoma of bone may arise within the medulla (central) or periosteal surface (peripheral) and have been reported to occur secondary to heavy radiation exposure, Paget's disease, bone infarcts, fibrous dysplasia and giant cell tumors. It is distinguished from other bone sarcomas by the presence of spindle-shaped tumor cells among interlacing bundles of collagen without any formation of cartilage or bone. Primary fibrosarcomas of bone may occur at any age, but tends to predominate in the 3rd to 5th decades of life. There is no clear male or female predominance. The distal femur and proximal tibia are the most common sites of the lesion and distal metastasis. Wide resection with or without adjuvant therapy is the treatment of choice. Various types of fibrosarcomas have been identified based on clinical, radiographic and histologic features, including medullary, periosteal, secondary, multifocal and infantile. In the few studies that have reported on fibrosarcoma of bone in children it appears that they have a favorable prognosis. The most important prognostic factors that affect survival include patient age, tumor location, and tumor grade.
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