Unmasking Tuberculosis: Bronchial Anthracofibrosis as a Diagnostic Clue

Abstract Introduction: Bronchial anthracosis (BA), the accumulation of carbon particles, is visualized as darkly pigmented bronchial mucosa on bronchoscopy. BA develops in some patients after exposure to biomass combustion. Chronically, BA with airway inflammation may progress to bronchialanthracofibrosis (BAF), which has radiographic features of multifocal bronchial narrowing and peribronchial cuffing, and parenchymal findings of nodules or masses. BAF predisposes to infection, malignancy, and chronic respiratory disease. This case sheds light on the diagnostic workup of BAF, the importance of having mycobacterium tuberculosis (MTB) on the differential, and urges a broader understanding of “classic exposures” in light of climate change. Case: A 77-year-old male never-smoker presented with massive hemoptysis after one year of dry cough and 20-lb weight loss. CT chest (Figure 1B) revealed a 3x2x4cm mass in the right middle lobe (RML) and right hilar lymphadenopathy. Bronchoscopy showed areas of black-blue mucosa, malignant appearing infiltration of the proximal right upper lobe segment, and narrowing of the left lower lobe airways (Figure 1A). Endobronchial ultrasound-guided fine needle aspiration of lymphadenopathy and endobronchial biopsies were completed. Cytopathology was negative for malignancy. With high suspicion for cancer, repeat bronchoscopy with biopsy showed atypical squamous cells but lacked severe atypia, precluding a definitive diagnosis of malignancy. After hemoptysis resolved, the patient was dischargedwith follow-up. He was born in the Dominican Republic but immigrated to Puerto Rico thirty-five years ago where he worked as a security guard for a factory. He had recently moved to Rhode Island to be with family. He denied inhalational or MTB exposures and had no significantfamily history. Sputum cultures grew MTB within 48 hours. He was treated for pan-sensitive MTB with resolution of symptoms and near resolution of the RML mass (Figure 1C). Discussion: Bronchial anthracosis and anthracofibrosis have primarily been described in elderly women with chronic inhalation of smoke from indoor cooking. BAF is associated with tuberculosis though the association may reflect the higher incidence of MTB in countries where indoor biomass smoke exposure is more common. In our case, pathology revealed parenchymalchanges, fibrous tissue, and anthracotic pigment consistent with BAF. A concurrent infectious work-up diagnosed MTB. The patient had no domestic or social history typical for BAF, but chronic exposure to air-pollution was likely given his occupational proximity to industry. Whilecertain populations continue to use biomass stoves, the effects of climate change, namely urban air pollution and wildfires, may increase risks for BA, BAF, and ultimately MTB.