A giant retrofemoral Baker's cyst.

A hundred years ago, in 1877, the Englishman, W. Morrant Baker, published his first report “On the formation of synovial cysts in the leg in connection with disease of the knee-joint”. Although other authors before Baker described the same disease, the expression “Baker's cyst” has remained the common term in medical language. Usually the cyst communicates with the joint, either directly or via the bursae in the popliteal fossa (Baker, 1885). The incidence of popliteal cysts in autopsies has been reported to be approximately 50% (Wilson et al., 1938) and the development of arthrography has enlarged our knowledge of the anatomy of these cysts.