Abstract
RATIONALE: Multicentric Castleman disease (MCD) is a rare lymphoproliferative disorder accompanied by systemic symptoms characterized by polyclonal hypergammaglobulinemia and chronic inflammation due to overexpression of interleukin-6. Histological heterogeneity of renal involvement in MCD has been described, although the number of reports is limited. Tocilizumab, a humanized anti-interleukin-6 receptor antibody, has been reported to be effective for MCD. PATENT CONCERNS: A 64-year-old man experienced refractory anemia and slowly progressive renal dysfunction with proteinuria, accompanied by persistent inflammation for 11 years. DIAGNOSIS: Two renal biopsies were obtained. The first biopsy performed 7 years before admission revealed non-specific interstitial inflammation, whereas the second biopsy demonstrated global sclerosis in most glomeruli and interstitial fibrosis. The patient had multiple lymphadenopathies. Cervical lymph node biopsy histological findings were compatible with plasma cell type Castleman disease. The patient had no evidence of human hepatitis virus-8 infection. INTERVENTION: The patient was treated with 60 mg/d prednisolone followed by 8 mg/kg intravenous tocilizumab every 2 weeks. OUTCOME: His anemia significantly improved, as well as a marked reduction in proteinuria and stabilization of renal function. He did not experience renal function during the 2-years follow-up period. LESSONS: The heterogeneity of the renal manifestations of MCD sometimes makes early diagnosis difficult. We need to interpret the histological findings of the renal biopsy carefully. For advanced-stage renal diseases, tocilizumab might be an effective treatment strategy for MCD.