Castleman disease or angiofollicular hyperplasia is a rare disorder included in the group of lymphoproliferative disorders. This entity was originally described by Castleman in 1956. The etiology remains unknown but it is postulated to be a reactive lymphoid hyperplasia due to chronic antigenic stimulation caused by a viral infection. The disease presents in young adults and is more frequent in women; it is exceptionally rare in the pediatric age group. It is classified into two clinical groups (localized disease and disseminated disease) and there are two histologic variants (hyaline-vascular and plasma cell Castleman disease). Localized disease is usually asymptomatic, has a good prognosis, and is the most common presentation in pediatric patients, usually corresponding to highly vascularized mediastinal masses. Resection of the mass, which is curative, is associated with a high risk of blood loss. Recently, preoperative arteriography with embolization has been used satisfactorily in the preoperative management of these tumors. We present a case of localized Castleman disease in a 12-year-old girl satisfactorily treated with embolization before curative resection.