Micro-Computed Tomography Based Whole Block Imaging of Asthma-Associated Airway Remodeling With Mycobacterium avium-Induced Cavity Formation: 3-Dimensional Nondestructive Analysis

Asthma is a recognized risk factor for nontuberculous mycobacterial (NTM) pulmonary infections, yet the precise routes of infection and dissemination remain visually unclear. We analyzed a rare surgical case of asthma complicated by Mycobacterium avium–associated lung cavity formation in a young adult. Following antibiotic treatment, the patient underwent left upper segmentectomy, with successful subsequent treatment of residual lesions using amikacin liposome inhalation suspension. To precisely visualize the infection route, we utilized a three-dimensional merged whole block imaging (WBI) technique. Fifteen formalin-fixed paraffin-embedded tissue blocks from the resected lung were individually scanned using a custom-built micro-computed tomography system, reconstructed, and combined to generate merged-WBI. Three core merged-WBIs revealed that the remodeled asthma-associated airway ascended from the proximal hilar region, intertwined with surrounding epithelioid granulomatous tissue, and then descended into a subpleural cavity composed of epithelioid granulomas with central caseous necrosis containing acid-fast bacilli. Besides the distinct airway path, the WBI delineated the distribution of minor epithelioid granulomas and calcifications. This report provides the first three-dimensional visualization of a continuous airway route extending from the hilum to a subpleural cavity using merged-WBI, suggesting bronchial spread as a probable mechanism of NTM dissemination in the setting of chronic airway disease. Clinical trial registration: No clinical trials.