Chronic Eosinophilic Pneumonia Masquerading as a Lung Mass.

Lung masses are becoming more common, and although most are tumors, benign or malignant, some are not solid masses. Many pathologies can present as lung nodules, including lung cancers, hamartomas, lung abscesses, granulomas, and eosinophilic pneumonia, to name a few. A 40-year-old woman with a long history of smoking presented with cough and left-sided chest pain. After multiple imaging studies, she was thought to have a lung malignancy; however, multiple biopsies proved this was not the case. The histology reports of 3 to 4 biopsies at separate times indicated chronic inflammation ongoing in the lungs without any cancer cells present. She was treated for chronic eosinophilic pneumonia with a resolution of symptoms. The purpose of this case report is to discuss a case that was initially thought to be a lung mass but found to be chronic eosinophilic pneumonia manifesting as a lung mass.