[A case of exostosis of the base of the acetabulum in a child with multiple exostoses].

The authors report a case of an exostosis of the base of the acetabulum seen at the age of four months in a routine radiograph of the pelvis in a child suffering from osteochondromatosis. The growth in size of this exostosis led to subluxation of the hip at the age of three years. Surgical removal resulted in reduction of the subluxation and restoration of joint stability three years after operation. An intra-acetabular site for an exostosis has rarely been described.