The acute fibrinoid and organizing pneumonia (AFOP) is an histophatological pattern featured for the presence of intra-alveolar fibrin and organizing pneumonia (1). AFOP is an entity that can be either idiopathic or associated with several clinical conditions, including infectious diseases, drug interactions and cancer. No specific treatment exists for AFOP but an excellent response to steroids therapy is observed. AFOP is still a not well understood entity and is defined with a distinct histological pattern that can appear adjacent to other entities, including hematologic malignancies. A 55-year-old man was admitted in hospital with pneumonia diagnosis, that had no response to antibiotics, but an excellent response to steroids. The lung biopsy supported the diagnosis of AFOP.

Keywords: Organizing pneumonia, fibrin, hematological malignancy, glucocorticoids