A case of hut lung: scanning electron microscopy with energy dispersive x-ray spectroscopy analysis of a domestically acquired form of pneumoconiosis.

Hut lung is a pneumoconiosis caused by exposure to smoke derived from biomass fuels used for cooking in poorly ventilated huts. We report, to our knowledge, the first analysis of the dust deposited in the lungs in hut lung by scanning electron microscopy with energy dispersive x-ray spectroscopy (SEM/EDS). A Bhutanese woman presented with shortness of breath and an abnormal chest radiograph. Chest CT scan showed innumerable tiny bilateral upper lobe centrilobular nodules. Transbronchial biopsy revealed mild interstitial fibrosis with heavy interstitial deposition of black dust. SEM/EDS showed that the dust was carbonaceous, with smaller yet substantial numbers of silica and silicate particles. Additional history revealed use of a wood/coal-fueled stove in a small, poorly ventilated hut for 45 years. The possibility of hut lung should be considered in women from countries where use of biomass-fueled stoves for cooking is common. Our findings support the classification of this condition as a mixed-dust pneumoconiosis.