Cat-scratch disease mimicking rhabdomyosarcoma

A 12-year-old boy who had injured his elbow presented with a lump in the epitrochlear area. Originally thought to be a hematoma, then later myositis ossificans, this mass was actually a lymph node with large, reactive germinal centers. Although stains for acid-fast bacilli, fungal organisms, bacteria, and cat-scratch disease were negative, serological testing for detection of Rochalimaea henselae organisms found evidence of cat-scratch disease. We would like to remind orthopaedic surgeons to consider this diagnosis in evaluating masses of the soft tissues of the extremities.