[Acute orbital myositis and idiopathic inflammatory pseudotumor in children: three cases]

Orbital pseudo-tumors account for approximately 8% of the orbital tumors. They are scarcely described in children and raise diagnostic dilemas, especially when they present as an isolated extra-ocular muscle swelling called idiopathic orbital myositis (IOM).

A diagnosis of inflammatory orbital pseudotumors (IOPT) was made in three children aged 7, 13 and 14 years from clinical and CT scan and/or MRI findings associated with histological data in two of them. Two of these IOPT presented as IOM. Analysis was made in a effort to eliminate intra-orbital tumors, especially rhabdomyosarcoma.

The abrupt onset of the orbital signs, often related in the literature, was not a specific diagnostic criterion regarding to embryonic rhabdomyosarcoma. The inconstant presence of inflammatory signs and the absence of local osseous defect could be more discriminating. Although diagnostic procedure, including histological documentation, was difficult, even dangerous, surgical biopsy should be recommended. Eventually, considering the mandatory multidisciplinary care, steroid therapy response should be evaluated as a diagnostic test.