An Unusual Presentation of Acute Fibrinous and Organizing Pneumonia

BACKGROUND Acute fibrinous and organizing pneumonia (AFOP) is a newly evolving rare non-infectious lung pathology, characterized by intra-alveolar fibrin balls on histology. It is often difficult to diagnose and is usually mistaken for other lung pathologies. We present an interesting case of AFOP with unusual radiologic findings and disease course. CASE REPORT A 56-year-old woman presented with a 1-day history of high-grade fever, chills, and profuse sweating. She was febrile to 101.2 degree Fahrenheit on presentation. On physical examination, she had decreased air entry in the left upper lobe of the lung. Laboratory testing showed a white cell count of 27,000 cells per microliter of blood with left shift. A chest radiograph showed a left upper lobe consolidation. Computed tomography (CT) of the chest without intravenous contrast showed advanced centrilobular emphysema and left upper lobe consolidation measuring 6.2×5.9 cm. The patient was started on antibiotics. She clinically improved and was discharged on oral antibiotics. After discharge, a trans-bronchial lung biopsy showed acute inflammatory cell infiltrate with intra-alveolar fibrin balls but no hyaline membrane formation or significant eosinophils. These findings were consistent with acute fibrinous and organizing pneumonia. However, she was subsequently lost to follow-up. CONCLUSIONS Our case adds to the literature a new and unusual finding of upper lobe infiltrates, in contrast to most cases presenting as bilateral lower lobe infiltrates. In our case, symptomatic improvement after antibiotic treatment suggests a possible role of antibiotics in management of this entity.