Idiopathic plasmacytic lymphadenopathy: A conceptual history along with a translation of the original Japanese article published in 1980

Abstract

The current consensus on Castleman disease is that it is a group of several distinct lymphoproliferative disorders with different underlying pathogenesis and clinical outcomes. In 1980, Mori et al. proposed the concept of idiopathic plasmacytic lymphadenopathy with polyclonal hyperimmunoglobulinemia (IPL), a disease of unknown etiology, characterized by severe polyclonal hypergammaglobulinemia and generalized superficial lymphadenopathy. After Frizzera et al.'s landmark report in 1983, the term multicentric Castleman disease (MCD) gradually became established, and for a time, IPL was regarded as identical to MCD. However, with the subsequent recognition of human herpesvirus 8 (HHV8)-related MCD in the 1990s and the contributions by Kojima et al. in the 2000s, in which non-HHV8-related MCD (now called idiopathic MCD) was at least subclassified into IPL and others (non-IPL), it is now clear that the original distinctiveness of IPL is still maintained in MCD, which is a diverse collection of diseases.

Keywords: IPL; MCD; TAFRO syndrome; iMCD; idiopathic plasmacytic lymphadenopathy.

Fig. 1

Evolution of the concept of Castleman disease

Fig. 2

Histopathology of Castleman disease, hyaline vascular-subtype Branched vessels with focal hyalinization are observed in the follicle. In this follicle, several regressive germinal centers are grouped by fusion of the thick mantle zones, in which small lymphocytes are concentrically arranged.

Fig. 3

Histopathology of Castleman disease, plasma cell-subtype The germinal center is well-demarcated from the mantle zone and does not harbor highly branched and hyalinized vessels, clearly different from the vascular changes in the germinal centers of Castleman disease, hyaline vascular-subtype. The mantle zone constitutes concentrically arranged small lymphocytes but is not very thick. Plasmacytosis is observed immediately adjacent to the mantle zone, associated with vascular proliferation.