[Orbital idiopathic inflammatory orbital myositis in a child: case report ].

Idiopathic inflammatory orbital myosites represent 10% of the orbital pseudotumors and 8% of the orbital pathologic processes in children. They are rarely described although they raise real diagnostic problems. The authors report the case of a 10-year old little girl who presented sudden proptosis. The clinical and radiological work up and the therapeutic test with corticosteroids were in favor of an inflammatory orbital myositis. The authors remind the clinical, radiological, and therapeutical aspects of this entity that remains very unfrequent in children and needs to be differenciated from rhabdomyosarcoma.