<unk>  (also known as malignant synovioma) is a very rare form of soft tissue sarcoma, which usually occurs near the joints in upper and lower extremities.<unk>  was first discovered by Pack and Tabah in 1955.<unk>  may be classified according to histopathological findings into 4 sub-types: biphasic, monophasic fibrous (most common), monophasic epithelial, and poorly differentiated. The pathogenesis of<unk>  is characterized by the dysregulation of gene expression of SYT-SSX gene. The most common locations for the occurrence of<unk>  include Knee, adjacent to large joints, and Popliteal fossa. The SYT-SSX fusion gene (located in chromosome 18) has been associated with the development of<unk> . There are no established causes for<unk> .<unk>  must be differentiated from other diseases that cause joint pain, mass growth, and limited range of motion, such as malignant fibrous histiocytoma (MFH)-fibrosarcoma, Liposarcoma, Osteosarcoma, and Chondrosarcoma. The prevalence of<unk>  remains unknown.<unk> s account for 2.5 - 10% of all soft tissue sarcomas.<unk>  is more commonly observed among patients aged 15 - 40 years old. There is no racial predilection for<unk> . There are no known risk factors associated with the development of<unk> . There is insufficient evidence to recommend routine screening for<unk> . The majority of patients with<unk>  remain asymptomatic for years. If left untreated, patients with<unk>  may progress to develop metastases. Prognosis is generally poor, and the median survival rate of patients with<unk>  is approximately 35% to 60%. The diagnosis of<unk>  is typically made based on histology and is confirmed by the presence of t(X;18). There are no specific laboratory findings associated with<unk> . Patients with<unk>  usually are well-appearing. There are no specific laboratory findings associated with<unk> . There are no ECG findings associated with<unk> . Plain x-ray can be normal unless the tumor is large in size or has dystrophic calcifications. On ultrasound, characteristic findings of<unk>  include heterogeneity and hypo-echoic mass. On CT scan, characteristic findings of<unk>  include Soft tissue mass, calcifications, and Heterogeneous density and enhancement. MRI is the imaging modality of choice for<unk> . Medical therapy include Doxorubicin, ifosfamide, and gemcitabine. Surgery is the mainstay of therapy. Surgical resection in conjunction with chemotherapy or radiation is the most common approach to the treatment of<unk> . There are no established measures for the prevention of<unk> .
Synovial sarcoma
Osteochondroma
Osteoblastoma
Osteosarcoma
Ewing's sarcoma
Chondrosarcoma
Osteoma
Osteochondrosis