Cryptogenic Organizing Pneumonia Medical Slides

Present the reversed halo (atoll) sign: a focal rounded area of ground-glass opacity surrounded by a near-complete ring of consolidation. While characteristic of COP, it is present in only ~20% of cases and is not pathognomonic — also seen in paracoccidioidomycosis, mucormycosis, granulomatosis with polyangiitis, and pulmonary infarction. More common COP HRCT findings include bilateral peripheral or peribronchovascular consolidations (often migratory on serial imaging), ground-glass opacities, and band-like opacities.

Present the standard protocol: prednisone 0.75-1 mg/kg/day (typically 40-60 mg) for 4-8 weeks, then taper to 0.5 mg/kg/day for 4-6 weeks, then 20 mg for 4-6 weeks, then gradual taper by 5 mg every 2-4 weeks. Total duration: 6-12 months minimum. Clinical response is typically dramatic within 1-2 weeks with radiographic improvement by 2-4 weeks. Relapse on taper occurs in 30-50% of patients — usually responds to dose increase. Second-line agents for steroid-dependent patients: azathioprine or mycophenolate.

Present the clinical scenario that triggers COP evaluation: patient with bilateral consolidations treated with ≥2 courses of antibiotics without improvement. Key distinguishing features: COP — subacute onset (weeks-months), mild systemic symptoms, restrictive PFTs, elevated ESR/CRP, bilateral patchy consolidations (often migratory); CAP — acute onset, fever/rigors, productive cough, leukocytosis, typically unilateral/lobar. BAL in COP shows mixed cellularity (lymphocytes 20-40%, neutrophils, eosinophils). Tissue biopsy showing Masson bodies (buds of granulation tissue filling alveolar ducts and alveoli) confirms the diagnosis.