Presentation
Shortness of breath.
Patient Data
Diffuse, coarse reticulonodular airspace opacities throughout the bilateral lung fields with superimposed confluent areas best seen in the right mid-lung.
Normal lung volumes.
Pulmonary vasculature is obscured. No pneumothorax or pleural effusion.
Cardiomediastinal silhouette is unremarkable.
The lungs show diffuse pulmonary micronodules in a broncho-vascular distribution with concurrent areas of consolidation.
There is no pleural thickening, effusion or pneumothorax.
The airways are clear.
There are calcified hilar and mediastinal lymph nodes.
Heart size is normal. No pericardial effusion.
FDG PET-CT
FDG PET-CT shows moderate to intense FDG avidity associated with micronodules and consolidations (SUV max 10.9). Moderate FDG avidity is associated with the calcified hilar and mediastinal lymph nodes (SUV max 5.6).
There are no findings of extrathoracic FDG avidity.
Additional history: recent emigree from Afghanistan. As an adult, conveys a long social history of cooking indoors with a wood-burning stove and poor ventilation.
Underwent lung biopsy and bronchioalveolar lavage, with results all negative for tuberculosis, other forms of infections, granulomatous disease and malignancy. The patient started on empiric anti-TB therapy with no response. FDG PET-CT negative for any acute extra-pulmonary findings.
Multidisciplinary care conferences including radiology, pathology, pulmonary, infectious disease and public health determined findings consistent with domestically acquired particulate lung disease (also known as 'hut lung' in the literature).
Final pathology diagnosis:
Lung, right lower lobe, core needle biopsy and touch preparations:
· alveolated lung parenchyma with extensive interstitial and nodular fibrosis and entrapped histiocytes with abundant anthracotic pigment.
· negative for granulomata and malignancy.
Comment:
Gomori methenamine silver and Ziehl-Nielsen stains are negative for fungal and acid-fast micro-organisms, respectively. Immunohistochemical studies show histiocytic cells are diffusely and strongly positive for CD68. Pancytokeratin (AE1/AE3) highlights entrapped alveolar cells. CD31 and CD34 highlight background lymphovascular structures. CD3, CD20 and PAX5 highlight background mixed inflammatory cells.
The histologic findings in a patient with history of significant exposure to cooking indoors with biomass fuel, such as wood, with poor ventilation as this patient endorses upon further history-taking, suggests a diagnosis of domestically acquired particulate lung disease.
Treatment focuses on avoiding any further exposure to the offending agent.
Case Discussion
Domestically acquired particulate lung disease (also known as 'hut lung') is a pneumoconiosis caused by recurrent exposure to the smoke of biomass fuels, typically from cooking in poorly ventilated structures such as huts.
In such settings, biomass fuels are burned in simple stoves with a high degree of incomplete combustion, resulting in a large number of particles and chemical compounds within the smoke.
The disorder manifests clinically with a wide range of pulmonary disorders such as chronic bronchitis to cor pulmonale and advanced pulmonary fibrosis.
On imaging, it may demonstrate ground glass opacities, pulmonary nodules (often upper lobe predominant), reticulation, peri-bronchovascular thickening and even progressive massive fibrosis.
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