Isolated microcytic anemia disclosing a unicentric Castleman disease: The interleukin-6/hepcidin pathway?

Castleman disease (CD) is a rare lymphoproliferative disorder of uncertain origin. Anemia is commonly reported and is related to an inflammatory mechanism. Occasionally an autoimmune hemolytic anemia appears as the leading clinical feature. Three histological types have been differentiated, a hyaline-vascular type (HV), a plasma cell type (PC), and a mixed type. Clinically CD is separated into unicentric (localized) or multicentric (generalized) forms. The former is most frequently of HV type (80-90%), affecting a single lymph node. The PC type is encountered in 10-20% of the unicentric CD and in almost all of the multicentric cases. Numerous systemic manifestations have been described usually associated with PC type. An isolated and markedly microcytic anemia revealing a unicentric CD has never been reported in English literature. Recent data concerning iron metabolism, interleukin-6 and hepcidin provide interesting clues to understand the particular microcytic anemia of CD.