Clinical and imaging features of cryptogenic organizing pneumonia and secondary organizing pneumonia

Objective Organizing pneumonia (OP) is a distinct clinical and pathologic entity.This condition can be cryptogenic (COP) or secondary to other known causes (SOP). Methods The medical records of 54 patients with biopsy-proven OP were retrospectively reviewed.26 patients were diagnosed with COP and 28 patients with secondary OP.The clinical presentation, radiographic studies, laboratory data, biopsy methods, pathology, treatment, and outcome were analyzed. Results The mean age at presentation was (58.38±17.73) years.Cough, expectoration, fever, patchy consolidation were the most common symptoms and imaging findings.After 6 months of follow-up, the recurrence rates of patients in the COP and SOP groups were 37.8% and 9.4%, respectively.There was no significant difference in clinical and imaging findings between COP and SOP patients.Reversed hato sign was more common in the COP group.Higher blood levels of antinuclear antibody (ANA) was more common among patients with secondary OP.There was no significant difference in the recurrence rates between COP patients and SOP patients. Conclusions The clinical and radiographic findings in patients with COP and secondary OP are similar and nonspecific.COP and SOP have similar treatment response, relapse rates. Key words: Cryptogenic organizing pneumonia; Secondary organizing pneumonia; Clinical features; Radiographic features