Anemia and autoimmunity markers in an adolescent with Castleman disease.

We describe herein the case of an adolescent girl with anemia non-responsive to oral iron, associated with low-grade fever, diminished appetite and fatigue. A palpable mass below the xiphoid was noted. Laboratory findings were consistent with anemia of inflammation. Direct antiglobulin test was positive without any other evidence of autoimmune anemia. Other autoantibodies, such as anti-thyroid and anti-nuclear antibodies, were also positive. After thorough investigation, Castleman disease was the most likely diagnosis on the basis of high serum interleukin (IL)-6 and the magnetic resonance imaging findings. (18)F-FDG positron emission tomography-computed tomography showed a localized hypermetabolic mass, which was resected. Castleman disease of plasma type was identified on histology. Hemogloblin and IL-6 gradually returned to normal, whereas positive autoantibodies became negative. This case emphasizes the need to investigate thoroughly for the underlying cause of anemia of inflammation and to include Castleman disease in the differential diagnosis, on the measurement of IL-6.