Multiple relapses of cryptogenic organizing pneumonia: A case report.

Cryptogenic organizing pneumonia (COP) is an important subtype of idiopathic interstitial pneumonia, triggered by abnormal inflammatory responses of the lung to unknown stimuli. The disease shows good initial sensitivity to glucocorticoid therapy, but ~50% of patients experience recurrence after glucocorticoid dose reduction or withdrawal. Cases of multiple recurrences (≥3 times) are rarely reported clinically, and no unified consensus has been formed on their diagnosis and treatment strategies, making clinical management challenging. In the present study, a 53-year-old female patient was admitted to hospital for the first time, presenting with a recurrent cough for >1 month. Chest computed tomography (CT) revealed multiple areas of increased density in both lungs, with no notable absorption of the lesions following antimicrobial therapy. A CT-guided percutaneous lung biopsy revealed widened alveolar septa with numerous fibroblast clusters and foam cells within the alveolar spaces, consistent with a diagnosis of COP. Following treatment with methylprednisolone combined with anti-infective therapy, the lesions largely resolved. The patient was discharged on a tapering regimen of oral prednisone, completing a total treatment course of 2 months. After discontinuing medication for 18 months, the patient was readmitted due to chest tightness. CT revealed recurrence of the bilateral pulmonary lesions. Treatment with methylprednisolone combined with anti-infective therapy was administered. Following discharge, oral methylprednisolone therapy for 5 months resulted in complete resolution of the lesions. After 16 months of low-dose oral methylprednisolone maintenance therapy, the patient presented for a third visit with a cough and chest tightness. Chest CT confirmed recurrence of the COP. Symptoms improved after oral prednisone administration, but radiographic changes remained minimal. Multiple recurrent COP has clinical characteristics of migratory lesions, glucocorticoid sensitivity and easy recurrence, and a pathological biopsy is the key to its diagnosis. Long-term glucocorticoid maintenance and individualized dose reduction regimens may reduce the risk of recurrence, but the optimal treatment plan still needs to be explored in further clinical studies. The present case can provide a practical reference for the diagnosis and treatment of multiple recurrent COP.