Plastic bronchitis: a narrative review of the classification methods and pathogenesis

Plastic bronchitis (PB) is a rare but potentially life-threatening disorder characterized by bronchial cast formation and airway obstruction. This narrative review synthesizes the evolution of PB classification and, in particular, integrates emerging evidence supporting a subtype-oriented framework-lymphatic vs. eosinophilic PB-based on distinct etiologies and pathophysiological mechanisms. We searched PubMed, Embase, Cochrane Library, and Web of Science for relevant clinical and experimental studies and reviews published up to February 2026, focusing on classification, mechanisms, diagnostic approaches, and therapies. We summarize key mechanistic pathways and the practical implications of advanced lymphatic imaging (e.g., DCMRL, CT lymphangiography) and immunopathology for improving subtype-specific diagnosis, guiding mechanism-based treatment beyond supportive care, and interpreting therapeutic responses. Finally, we highlight major knowledge gaps and propose priorities for future translational and clinical research to refine diagnostic criteria and develop precision therapies for PB subtypes.