A42-06 Clearing the Smoke: Cavitary Organizing Pneumonia After Burn Pit Exposure

Abstract Organizing pneumonia (OP) is a form of interstitial lung disease that can resemble infectious, inflammatory, or malignant processes. Our case demonstrates an unusual presentation of OP as a large cavitary lesion radiographically concerning for malignancy in a patient with prior military burn pit exposure. This highlights the diagnostic challenge posed by atypical imaging and the potential role of environmental exposures in OP pathogenesis. A 45-year-old male never smoker with prior burn pit exposure during his tours in Iraq and Afghanistan, presented with two weeks of right-sided pleuritic chest pain, productive cough with dark brown sputum, and malaise. Four days prior, he was treated for presumed pneumonia with doxycycline, steroids, and albuterol, but symptoms persisted. Physical examination was unremarkable. Initial CT imaging showed a 5.5 cm right upper lobe mass-like consolidation, prompting a PET/CT scan, which revealed a 4.2 × 5.0 cm pleural-based hypermetabolic mass with hypermetabolic mediastinal lymphadenopathy. Robotic bronchoscopy along with EBUS/TBNA showed atypical glandular cells without diagnostic evidence of malignancy and histologic features of organizing pneumonia. A subsequent CT-guided biopsy revealed fibrosis, alveolar septal thickening, and fibroblastic reaction consistent with organizing pneumonia. The patient was started on prednisone 50 mg daily for one month, leading to symptom resolution and radiographic improvement with residual cystic cavity. This case underscores the diagnostic complexity of organizing pneumonia (OP) in a patient with prior burn pit exposure. The overlap in clinical presentation, risk factors, and imaging findings between OP and malignancy has been documented before, with both entities presenting as mass-like consolidations with pleural involvement, spiculation, and/or lymphadenopathy. This can delay proper diagnosis and therapy. Advanced imaging modalities, including CT radiomics and MRI, have shown promise in differentiating focal OP from peripheral lung cancer, but significant overlap remains. Features such as pleural adhesion, lesion location, liquefaction necrosis, and cavity formation may favor OP, while irregular margins and persistent lymphadenopathy are more suggestive of malignancy. No single imaging feature is definitive, and histopathologic confirmation remains the gold standard for diagnosis. OP can be cryptogenic or secondary to infection, pharmacologic toxicity, or connective tissue disease. Exposure to military burn pits is known to cause increased airway dysfunction and inflammation but, unlike inhalation injury from textile dyes or mustard gas, has yet to be directly linked to OP. Further research on the environmental risk factors of OP is warranted, particularly in our veterans exposed to burn pits. This abstract is funded by: None