Resection of organizing pneumonia with leftover adjacent cystic squamous lung carcinoma: A case report and literature review

The aim of the present case report was to investigate the clinical manifestations, imaging features and changes of tumor markers of organizing pneumonia (OP) complicated by squamous lung carcinoma with cystic air space (LC-CAS). A patient with OP resection and leftover adjacent LC-CAS complicated by pneumothorax was evaluated. Relevant reports of OP cases complicated by LC-CAS before February 2022 were searched in the PubMed, EMBASE, Web of Science, China Biomedical Literature Service System, Wanfang Data, China Journal Network full-text database and China HowNet databases using 'lung cancer' OR 'lung cancer with cystic air space' AND 'organizing pneumonia' as retrieval terms. After screening relevant reports, no Chinese articles and only one English article (case report) were obtained. The patient in the literature showed signs of dry cough, tachypnea and fever during the early stage of the disease. Chest computed tomography (CT) revealed an irregular consolidation around the lower lobe of the right lung accompanied by a sign of bronchial inflation (usually indicated by a clear bronchial shadow seen in the diseased lung tissue area). A positron emission tomography-CT (PET-CT) scan and examination for tumor markers were not performed. OP secondary to LC-CAS was confirmed by bronchoscopy, and the patient was in a generally good condition 6 months after right lobotomy. The patient in the present case had no obvious discomfort during the early stage of the disease. Chest high-resolution CT showed that the LC-CAS had an irregular shape, uneven wall thickness and feeding vessels during the early stage, and cystic cavity consolidation during the later stage of the disease. PET-CT revealed that the OP exhibited increased ¹⁸F-fluorodeoxyglucose (¹⁸F-FDG) uptake, whereas the LC-CAS did not exhibit a high ¹⁸F-FDG uptake at the early stage, and that the level of tumor markers (such as neuron-specific enolase, cytokeratin 19 fragment and squamous cell carcinoma antigen) gradually increased. OP was diagnosed through histopathological examination. A total of 32 months after pulmonary lobectomy, bronchoscopy revealed endobronchial neoplasm, and LC-CAS was diagnosed through biopsy. In conclusion, the present case demonstrates that OP with LC-CAS is rare, and thus, prone to missed or delayed diagnosis. Therefore, good clinical judgment and continuous learning can help reduce misdiagnosis.