Tumors and tumor-like lesions arising from tendons are infrequent. Here we reviewed the anatomy of tendons and the common types of tumors and tumor-like lesions of tendons and their sonographic features. Primary malignant or metastatic tumors of tendons are very rare

while primary benign tumors and tumor-like lesions are relatively more common. Benign tumors of tendons occur as soft tissue masses which are usually painless or just slightly tender. The common types of benign tumors of tendons are giant-cell tumor

chondroma

osteochondroma

osteoma

neurinoma

cavernous lymphangioma

cavernous hemangioma

leiomyoma and fibrolipoma. About half of these tumors are giant-cell tumors. Primary malignant tumors of tendons usually occur during 40-60 years old and often arise in the lower extremity. They are mainly various sarcomas

including clear-cell sarcoma

synovial and epithelioid sarcoma. Metastatic tumors of tendons

which are common in the hand

usually occur by direct extension from tumorous skin

joint

or tendon sheath

and hematogenic metastases are extremely rare. Tumor-like lesions of tendons tend to occur in the hand. The most common types are tendon ganglia

epithelial cyst and xanthoma.