Abstract
The present study aimed to compare clinicopathologic features between idiopathic multicentric Castleman's disease (n=22) and IgG4-related disease (n=26). Histology was analyzed using lymph node and lung biopsies. The expression of IL-6 mRNA in tissue was also examined by in situ hybridization and real-time PCR. Patients with idiopathic multicentric Castleman's disease were significantly younger than those with IgG4-related disease (p<0.001). Splenomegaly was observed in only idiopathic multicentric Castleman's disease (p=0.002), while pancreatitis and sialo-dacryoadenitis were restricted to IgG4-related disease (both p<0.001). Serum IgG4 concentrations were commonly elevated at >135 mg/dL in both groups (p=0.270). However, the IgG4/IgG ratio in IgG4-related disease was significantly higher than that in Castleman's disease (p<0.001). Histologically, sheet-like plasmacytosis was highly characteristic of idiopathic multicentric Castleman's disease (p<0.001), while plasmacytic infiltration in IgG4-related disease was always associated with intervening lymphocytes. Similar to laboratory findings, the IgG4/IgG-positive plasma cell ratio, but not the IgG4-positive cell count, was significantly higher in IgG4-related disease (p=0.002). Amyloid-like hyalinized fibrosis was found in 6/8 lung biopsies (75%) of Castleman's disease. The over-expression of IL-6 mRNA was not confirmed in tissue samples of Castleman's disease by either in situ hybridization or quantitative real-time PCR. In conclusion, useful data for a differential diagnosis appear to be age, affected organs, the serum IgG4/IgG ratio, sheet-like plasmacytosis in biopsies, and the IgG4/IgG-positive cell ratio on immunostaining. Since IL-6 was not over-expressed in tissue of idiopathic multicentric Castleman's disease, IL-6 may be produced outside the affected organs, and circulating IL-6 may lead to lymphoplasmacytosis at nodal and extranodal sites.
Highlights
Castleman’s disease is a heterogenous entity typically presenting lymphadenopathy with characteristic histopathologic changes [1]
Cases of idiopathic” Multicentric Castleman’s disease (MCD) (iMCD) were diagnosed during 16 years from January 2002 to December 2016, while the total number of IgG4-related disease (IgG4-RD) cases diagnosed at our institutes in the same period was more than 250 with a part of the cohort reported in a previous study [21]
The present study identified differences in clinical presentation, laboratory findings, and histopathologic features between iMCD and IgG4-RD
Summary
Castleman’s disease is a heterogenous entity typically presenting lymphadenopathy with characteristic histopathologic changes [1]. It is classified as unicentric or multicentric with the former showing lymphadenopathy restricted to a single anatomical site and indolent clinical courses [1, 2]. In addition to lymph nodes, extranodal organs, the lungs and kidneys, may be involved [5,6,7,8,9,10] Another classification scheme of Castleman’s disease is based on its association with human herpes virus 8 (HHV8) infection. Recent studies have described MCD associated with thrombocytopenia, anasarca, fever, reticulin fibrosis/renal failure, and organomegaly (TAFRO) syndrome, which is another uncommon form of Castleman’s disease [11, 12]
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