Fibrosarcoma (fibroblastic sarcoma) is a malignant mesenchymal tumour derived from fibrous connective tissue and characterized by the presence of immature proliferating fibroblasts or undifferentiated anaplastic spindle cells in a storiform pattern. In humans it is usually found in males aged 30 to 40. [Source: Wikipedia ]

OrphaNet reference
May Cause
Anterior mediastinal lesion
Blow-out bone lesion
Bone blister
Bone lesion with fluid-fluid level
Bone sequestrum
Cardiac or pericardial neoplasm or cyst
Chest wall lesion
Cyst-like mandibular lesion
Cystic jaw lesion
Destructive nasopharyngeal mass in a child
Diametaphyseal bone lesion
Diaphyseal bone lesion
Enlarged iliopsoas muscle
Extratesticular tumor in scrotum
Ill-defined expansile radiolucent jaw lesion
Ill-defined lytic jaw lesion
Intramuscular soft-tissue tumor
Large destructive bone lesion
Laryngeal tumor
Localized soft-tissue calcification
Long rib lesion
Loss of inner cortical bone margin
Lucent lesion of the calcaneus
Lytic vertebral lesion
Malignant primary bone neoplasm
Metaphyseal bone lesion
Nasal cavity lesion
Nasopharyngeal lesion
Osteolytic lesion with calcium attenuation
Periapical radiolucency in jaw
Permeative osteolytic lesion
Radiolucent skull lesion
Renal parenchymal tumor
Sacral neoplasm
Sinonasal lesion
Sinus disease with bone destruction
Skull base lesion
Soft-tissue mass with adjacent bone erosion
Soft-tissue tumor in a child
Soft-tissue tumor in a young adult
Soft-tissue tumor in an older adult
Soft-tissue tumor with associated calcification
Soft-tissue tumor with prominent vascularity
Solitary bone lesion with expansile remodeling
Solitary ill-defined lytic metaphyseal lesion
Solitary large calcified soft tissue mass adjacent to bone
Solitary lytic diaphyseal bone lesion
Solitary permeative metaphyseal lesion
Solitary poorly demarcated osteolytic bone lesion
Solitary well-demarcated lytic bone lesion
Subcutaneous tumor
T2-hypointense musculoskeletal lesion
Temporal bone neoplasm
Tumor-like bone destruction with little periosteal reaction
Tumor-like bone surface lesion
Urethral tumor
Vertebral neoplasm