Fibrodysplasia ossificans progressiva (FOP) is a severe, rare, autosomal dominant, ectopic ossifying condition, with primary involvement of the skeletal muscles associated with skeletal abnormalities. This report concerns an 11-year-old boy suffering from FOP, who presented significant modification of the musculoskeletal structure of the thorax and problems with articular movements. The patient showed progress after treatment with ethane-1-hydroxy-1,1-diphosphonate (EHDP). In fact, using a scintiscanner we were able to observe a significant improvement in symptoms and a recovery of some of the active sites of ossification.