Individuals initially diagnosed with<unk>  had been characterized as young adults (mean age: 33 years) or children >5 years old (13% to 19% of all cases), although a more recent study reported that individuals first diagnosed with the disease ranged in age between 6 and 67 years (mean age: 45.6 year).<unk>  generally presents as a painless mass located in the subcutaneous or subfacial (i.e. beneath the skin) tissues of the upper or<unk> er limbs, trunk, or, less commonly, the head and neck areas or within the gastrointestinal tract, heart, kidney, brain, retroperitoneum, mediastinum, or abdominal cavity. Tumors occurring in subcutaneous and subfacial tissues are often 3–11 cm in size (largest diameter) but in sites where the tumor can go undetected for long periods such as the buttocks, mediastinum, or abdominal cavity have been reported to be as large as 25, 23.5, and 50 cm, respectively. Magnetic resonance imaging and computed tomography scans often give results suggesting that a tumor is a<unk> .
Low-grade fibromyxoid sarcoma
Solitary fibrous tumor
Undifferentiated pleomorphic sarcoma
Ossifying fibromyxoid tumour
Sclerosing epithelioid fibrosarcoma
Collagenous fibroma
Mammary-type myofibroblastoma
Aggressive fibromatosis