Iron-refractory microcytic anemia as the presenting feature of unicentric Castleman disease in children.

Chronic, iron-refractory, microcytic anemia can be a diagnostic and therapeutic challenge. We report the cases of 2 children with occult, unicentric Castleman disease whose primary presenting feature was a chronic, unexplained, iron-refractory, microcytic anemia. Diagnosis was delayed because neither child had palpable lymphadenopathy and the lymphoproliferation was intra-abdominal. Surgical resection cured the anemia and the Castleman disease. A diagnostic clue to Castleman disease is an elevated concentration of interleukin-6 in blood, which causes anemia by inducing the expression of the iron-regulatory hormone hepcidin.