Secondary organizing pneumonia

Secondary organizing pneumonia (SOP) refers to organizing pneumonia that can be attributed to a specific cause, in contrast to cryptogenic organizing pneumonia (COP) in which no cause is present.

Pathology

Etiology

SOP can be attributed to the following causes :

Prior infection
  • bacteria
    • atypical pneumonia (e.g. Legionella, Mycoplasma etc.)
    • Streptococcus pneumoniae
    • Staphylococcus aureus
    • Pseudomonas aeruginosa
  • fungi
    • Cryptococcus neoformans
    • Pneumocystis jiroveci
    • Penicillium janthinellum
  • viruses
    • adenovirus, herpes, CMV, influenza, HIV, RSV, COVID-19
  • parasites
    • Plasmodium vivax
    • Dirofilaria immitis
Drugs
  • antimicrobials
    • amphotericin B, cephalosporins, nitrofurantoin, minocycline
  • chemotherapeutics
    • bleomycin, busulfan, chlorambucil, doxorubicin, trastuzumab
  • interferons
  • methotrexate
  • amiodarone
  • phenytoin
Miscellaneous