Castleman disease variant of polyneuropathy, organomegaly, endocrinopathy, monoclonal protein and skin changes syndrome: A case report

BACKGROUND Polyneuropathy, organomegaly, endocrinopathy, monoclonal protein and skin changes (POEMS) syndrome is a rare plasma cell neoplasm with associated paraneoplastic syndrome. Castleman disease variant of POEMS syndrome, lacking detectable M-protein is uncommon and presents substantial diagnostic and therapeutic challenges. We illustrate a case of Castleman disease variant of POEMS syndrome and the complexity of its clinical management. CASE SUMMARY A 56-year-old man presented with limb weakness, sensory neuropathy, weight loss, and hyperpigmentation. He was diagnosed with Castleman disease variant of POEMS syndrome, having fulfilled 3 major criteria (polyneuropathy, Castleman disease, and vascular endothelial growth factor elevation) and 6 minor criteria (organomegaly, extravascular volume overload, endocrinopathy, skin changes, papilledema, and thrombocytosis). He received melphalan plus dexamethasone, followed by three cycles of cyclophosphamide while planning for an autologous stem cell transplant, but suffered from seizures and thrombotic episodes throughout the course of his treatment. He gradually improved over 5 months, with improvement in limb strength, reduced pigmentation, and reduced fluid retention, but eventually succumbed to his illness due to sepsis. CONCLUSION Although a monoclonal plasma cell disorder is a mandatory diagnostic criterion for POEMS syndrome, it may be minimal or undetectable in some patients with the Castleman disease variant who otherwise fulfil diagnostic criteria.