Atypical idiopathic orbital inflammation in a young girl.

A 7-year-old girl presented with chronic right periocular pain worst in abduction, edema, and proptosis with radiographic evidence of right medial rectus myositis. After a negative workup, she was diagnosed and treated for idiopathic orbital inflammation (IOI) with a brisk response to oral steroids. She returned 8 months later with left periocular pain worst in abduction, proptosis, and radiographic evidence of left lateral rectus myositis. She was treated for recurrent and alternating IOI with intravenous (IV) glucocorticoids with resolution. One year later, she recurred with similar left orbital signs and symptoms and was found to have a left inferior oblique myositis on MRI. She was treated with oral steroids and methotrexate with clinical resolution. Ten months later, she presented with left periocular pain worst on adduction and was found to have left medial rectus myositis on MRI. She was treated with IV steroids, IV immunoglobulin, and rituximab with resolution of all symptoms. She is currently maintained on methotrexate and oral glucocorticoids. The atypical pediatric case of IOI over a 4-year period is described in this study.