Airway-Predominant Mucous Membrane Pemphigoid Causing Recurrent Central Airway Obstruction: A Fatal Case and Review of Interventional Management.

Mucous membrane pemphigoid (MMP) is a chronic autoimmune blistering disorder that primarily affects mucosal surfaces. Although laryngeal and tracheal involvement occurs less frequently, airway disease can lead to irreversible cicatricial stenosis and life-threatening obstruction. Lower airway involvement is rare but increasingly recognized in the emerging entity termed "pemphigoid of the pulmonary system" (POPS). We report a 62-year-old man with remote, biopsy-proven MMP who developed progressive tracheobronchial involvement after years of clinical remission. He presented with worsening dyspnea, hemoptysis, and recurrent mucositis. Imaging demonstrated complete opacification of one hemithorax with mediastinal shift secondary to central airway obstruction. Bronchoscopy revealed severe subglottic stenosis, friable tracheobronchial mucosa, and near-complete occlusion of the left main bronchus by circumferential fibrotic membranes. Balloon dilation, cryotherapy, and mechanical debridement produced transient airway patency, but rapid restenosis recurred. Direct immunofluorescence from the oral mucosa confirmed an immunoglobulin A (IgA-predominant MMP. Despite high-dose corticosteroids and repeated bronchoscopic interventions, the patient developed refractory hypoxemic respiratory failure and died. Airway-predominant MMP is an uncommon but aggressive phenotype characterized by mucosal inflammation, friability, and rapidly progressive scarring. Diagnostic delays are common because airway biopsies often lack an intact basement membrane, and serologies are frequently negative or low-titer. Interventional bronchoscopy is central to management; balloon dilation and cryotherapy offer temporary relief, but restenosis is expected due to the underlying autoimmune fibrosis. Mortality remains high when airway involvement is recognized late, as reflected in the POPS case series. This case demonstrates the destructive potential of airway-predominant MMP and the importance of early recognition, prompt bronchoscopy, and multidisciplinary management. Clinicians should maintain a high index of suspicion for airway involvement in patients with recurrent mucosal disease or unexplained respiratory symptoms to prevent irreversible stenosis.