Idiopathic Multicentric Castleman Disease, Plasmacytic Variant: A Case Report

Abstract

Introduction: Castleman disease is a rare lymphoproliferative disorder whose diagnosis requires integrating clinical, imaging, and histopathological findings. It has a morphological classification (unicentric or multicentric) and a histopathological one (hyaline-vascular, plasmacytic, or mixed variants). The multicentric form may present the TAFRO phenotype (thrombocytopenia, anasarca, fever, renal dysfunction, and organomegaly), which can be potentially fatal. This case highlights aggressiveness, initial diagnostic discordance, and early therapeutic decisions in a tertiary-care oncology hospital. Case presentation: A 44-year-old man with progressive abdominal pain, vomiting, and constipation; with peritoneal signs and petechiae. CT showed bowel obstruction, hepatosplenomegaly, and generalized lymphadenopathy. Laparotomy with appendectomy was performed; lymph nodes were consistent with lymphoid hyperplasia. He developed anasarca, pleural effusions, ascites, thrombocytopenia, acute kidney injury, and elevated inflammatory markers. Diagnosis and interventions: A confirmatory axillary lymph node biopsy established idiopathic multicentric Castleman disease, plasmacytic variant, TAFRO phenotype. Escalated antibiotics, hemodialysis, dexamethasone, and a single dose of rituximab were administered; positron emission tomography demonstrated lymph nodes with moderate tracer uptake. He progressed to septic shock and multiorgan dysfunction and died despite mechanical ventilation and intensive support. Conclusions: Idiopathic multicentric Castleman disease with TAFRO phenotype can present fulminant clinical presentation. Early suspicion, repeating biopsies when clinicopathologic discordance exists, and timely access to advanced studies and targeted therapies are key to clinical outcomes. This case underscores the need for diagnostic protocols and early multidisciplinary management.