A Case of Recurrent Cryptogenic Organizing Pneumonia Complicated by Primary Pulmonary Malignant Lymphoma

Abstract

Background. Cryptogenic organizing pneumonia (COP) usually responds well to corticosteroid treatment and typically has a good prognosis. However, a few cases are refractory to corticosteroid treatment. Immunosuppressant drugs are associated with an increased risk of malignant lymphoproliferative disorders. Case. A 63-year-old man presented with a history of cough for a month. High resolution computed tomography (HRCT) of the chest showed air-space consolidation predominantly in both lungs. We diagnosed COP by transbronchial lung biopsy (TBLB) specimens. Clinical data and HRCT findings were improved by prednisolone therapy, but recurrent exacerbation occurred during steroid tapering. Although, we re-examined the abnormal lesions in the left lower lobe by video-assisted thoracoscopy and those in the right lower lobe by TBLB, histopathological examinations of all lesions revealed organizing pneumonia. We continued immunosuppressive therapy with a combination of prednisolone and immunosuppressive agents. However, lung lesions gradually deteriorated. In order to obtain a histopathological diagnosis again, we performed TBLB from the right lower lobe. Histopathological examination revealed lung invasion of diffuse large B cell type lymphoma. Conclusion. We experienced a rare case of recurrent COP complicated by primary pulmonary malignant lymphoma. It is necessary to pay attention to the possibility that malignant lymphoma may be involved in recurrent COP during immunosuppressive therapy.