Hyaline-vascular Variant Unicentric Castleman Disease with Paraneoplastic Pemphigus and Bronchiolitis Obliterans Treated with Rituximab: Case Report

Castleman disease (CMD) is an uncommon lymphoproliferative disorder characterised by hyperplasia of lymphoid tissue. There are three histopathologic types of CMD: hyaline-vascular type, plasma cell type and mixed type. Hyaline-vascular CMD is typically unicentric, while plasma cell CMD tends to be multicentric. In rare occasion, CMD can be associated with paraneoplastic pemphigus (PNP), an autoimmune syndrome which encompasses a multitude of mucocutaneous and systemic clinical features. In children with PNP associated with Castleman disease, they have been reported to have very poor prognosis and high mortality rate as a result of respiratory compromise despite aggressive treatment. We report a case of unicentric, CD-20 positive, hyaline-vascular retroperitoneal CMD presenting with paraneoplastic pemphigus and bronchiolitis obliterans with significant clinical improvement in oral mucositis and the prevention of tumour recurrence, using regular rituximab (375 mg/m(2)/dose) and 3-day course of pulse methylprednisolone therapy (10 mg/kg/day) after tumour resection.