Acute fibrinous and organizing pneumonia following hemophagocytic syndrome in two adult patients with hematological malignancies

Acute fibrinous and organizing pneumonia (AFOP) is a rare acute lung injury featuring pathological intra-alveolar fibrin balls and organizing pneumonia without hyaline membranes or eosinophils. AFOP forms acute and subacute patterns; the former often has a poor prognosis, whereas the latter has better survival. Secondary hemophagocytic syndrome (HPS) is a cytokine-related and potentially lethal disorder induced by various diseases, and pulmonary involvement in HPS is not rare. However, to our knowledge, no report has addressed the association between secondary HPS and AFOP development. We report two cases of subacute AFOP following HPS in hematological malignancies.