Unicentric castleman disease complicated by paraneoplastic bronchiolitis obliterans and pemphigus

Bronchiolitis obliterans (BO) and paraneoplastic pemphigus are rare and ominous complications of Castleman disease. Collectively, these processes have been reported as part of paraneoplastic autoimmune multiorgan syndrome (PAMS), and they can occur in the setting of various hematologic malignant tumors, carcinoid tumors, and melanoma. Irrespective of the underlying malignancy driving PAMS, the clinical outcomes are uniformly poor, and there are no standard treatment regimens, given the clinical rarity of the syndrome. We describe 2 patients with unicentric Castleman disease complicated by paraneoplastic pemphigus and bronchiolitis obliterans. In addition to primary surgical resection for Castleman disease, we also used therapy from a treatment protocol used for bronchiolitis obliterans resulting from hematopoietic stem cell transplant (HSCT). We were able to treat the patients using intravenous immunoglobulin; rituximab; fluticasone, azithromycin, and montelukast (FAM); and rosuvastatin therapy. One patient demonstrated a favorable response, while the other demonstrated minimal response to this therapy. Keywords: Bronchiolitis, Chest imaging, Leukotriene receptor antagonist, Multisystemic syndrome, Small airway disease