Endothelial Expansion Drives Vascular Hyalinization in Castleman Disease

Unicentric Castleman disease is a rare lymphoproliferative disorder that typically carries an excellent prognosis following complete surgical resection [1, 2, 3]. However, the clinical trajectory shifts dramatically when the disease is complicated by paraneoplastic pemphigus, a severe autoimmune mucocutaneous syndrome characterized by high mortality and life-threatening respiratory failure [4, 5]. In a retrospective study of 281 patients, bronchiolitis obliterans (an obstructive lung disease caused by small airway inflammation) occurred in 6.4% of cases and was associated with an 83.3% prevalence of paraneoplastic pemphigus [6]. While the hyaline-vascular histological subtype is the most common variant, current interventions often fail to halt the progression of pulmonary damage, as complete surgical resection does not consistently prevent the advancement of respiratory failure [7, 6, 8]. A recent transcriptomic analysis (a method used to study the complete set of RNA transcripts in a cell) of 33 patients now identifies aberrant endothelial cell expansion and extracellular matrix dysregulation as primary drivers of the vascular hyalinization and systemic immune dysfunction seen in these complex cases [4].