Clinicoradiological features of pulmonary infarctions mimicking lung cancer

OBJECTIVE: To describe presenting features of pulmonary infarction that may simulate those of lung cancer. PATIENTS AND METHODS: We reviewed the medical records of 43 patients with pulmonary infarction diagnosed by surgical lung biopsy at the Mayo Clinic in Rochester, Minn, from January 1, 1996, to December 31, 2002. Of 16 patients presenting with an undiagnosed solitary pulmonary nodule or mass, 6 had features suggestive of lung cancer on additional imaging, Including abnormalities on contrast-enhancement computed tomography (CT), positron emission tomography (PET), or nonsurgical lung biopsy before surgical resection. We examined the presenting symptoms, epidemiological, clinical, and radiological features, and clinical course of these 6 patients. RESULTS: All 6 patients, ranging in age from 41 to 85 years, had a history of smoking and underlying cardiopulmonary disease. In 5 of the 6 patients, CT showed a nodule in the subpleural region of the lung. Three patients had abnormalities on contrast-enhancement CT, 2 had abnormalities on PET, and 1 had abnormal cytologic findings on a transthoracic needle biopsy of the lung; all these studies showed abnormalities suggestive of lung cancer. Surgical resection of the nodule or mass revealed pulmonary Infarction associated with organizing thrombi in all 6 patients. CONCLUSIONS: Pulmonary infarctions can closely mimic the clinicoradiological characteristics of lung cancer, an association not reported previously. Furthermore, cytologic changes that occur in pulmonary infarctions may produce malignant-appearing cells on needle biopsy of the lung. The possibility of pulmonary infarction should be considered in the differential diagnosis of a solitary lung nodule or mass located in the subpleural region, even in the absence of clinically recognized-venous thromboembolism.