Fibrosarcomas usually arise deep to the subcutis, from fascia, including within muscle, or from aponeuroses or tendons. In this location, they may become attached to or encircle underlying bone. Very rarely, they may arise from the subcutaneous tissue. Trauma, chronic scarring, and prior irradiation have been implicated as causative factors.
Many tumors that were previously classified as fibrosarcomas have recently been reclassified as other fibroblastic tumors. Therefore, prognostic data may not be reliable, and further contemporary studies are needed. After excision, local recurrence rates were reported to approach 60% but were reduced to 25% when postoperative radiation was used. The 5-year survival rate was reported to be 40%-60% in adults.
Metastases often arise within 2 years of diagnosis, but in histologically low-grade tumors, they may take many years to develop. The tumor metastasizes primarily to the lung and bone.
Related topic: infantile fibrosarcoma
C49.9 – Malignant neoplasm of connective and soft tissue, unspecified
443250000 – Malignant fibromatous neoplasm
- Nodular fasciitis – Rapidly growing, painful mass presenting especially on the volar aspect of the forearm.
- Myositis ossificans – Presence of metaplastic bone, many times following an episode of trauma.
- Osteosarcoma – Produces tumor osteoid.
- Desmoid tumor – Histology shows a relative increase in collagen and absence of cytologic atypia.
- Monophasic synovial sarcoma – Histology may show focal calcifications, gland or gland-like spaces.
- Neurofibrosarcoma – Arises from an identifiable nerve; apparent neurofibroma components may be present.
- Liposarcoma – Histology shows lipocytes in well-differentiated tumors, or lipoblasts if less well-differentiated.
- Malignant peripheral nerve sheath tumor (MPNST)
- Undifferentiated pleomorphic sarcoma