[Nodular presentation of a cryptogenic organizing pneumonia].

Introduction: Cryptogenic organizing pneumonia is inflammatory and proliferative pulmonary diseases whose specific radiologic feature are bilateral and migrant opacities.

Observation: An isolated peripheral nodule of the left lower lobe was discovered on chest X-ray of a man who presented with isolated chronic cough. As this nodule has a positive FDG positron emission tomography uptake (PET) but with inconclusive fiberoptic bronchoscopy, the patient was sent to surgeon and a wedge-resection was processed because intraoperative analysis did not show any tumour. Histopathological study was in favour of organizing pneumonia. Search for potential cause remained negative and the diagnosis of cryptogenic organizing pneumonia was retained.

Conclusion: Cryptogenic organizing pneumonia may mimic lung cancer, presenting as an isolated peripheral nodule with positive PET. Histopathological study remains absolutely necessary to retain the diagnosis because of dramatic differences in prognosis and therapy.