Effectiveness of tocilizumab monotherapy for IgG4-related disease-like features caused by idiopathic multicentric Castleman's disease: a case-based review.
Koji Suzuki, Mitsuhiro Akiyama, Tomohiro Kaburaki et al.
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Case in brief
A 68-year-old woman presented with dyspnea associated with a recurrent laryngeal tumor, pulmonary consolidation, mediastinal and axillary lymphadenopathy, sclerosing mesenteritis, and retroperitoneal fibrosis. CRP and serum IgG4 were elevated, and laryngeal and pulmonary specimens showed IgG4-positive plasma-cell infiltration, suggesting IgG4-related disease. However, lymph-node histopathology established idiopathic multicentric Castleman disease (iMCD), diagnosed with IgG4-related-disease-like features. Tocilizumab monotherapy rapidly normalized CRP and IgG4 levels and improved organ involvement; she achieved long-term clinical remission without glucocorticoids.
What made this case unusual
Despite IgG4-related-disease-like organ involvement and tissue findings, lymph-node histopathology identified iMCD. The case also describes remission with tocilizumab monotherapy, without glucocorticoids.
Diagnostic / clinical pearl
Elevated serum IgG4 and IgG4-positive plasma-cell infiltration can occur in iMCD and do not alone establish IgG4-related disease; lymph-node histopathology was decisive in this case.