Pulmonary infections mimicking cancer: a retrospective, three-year review.

Pulmonary infections can mimic or occasionally co-exist with pulmonary neoplasms. In order to determine the frequency and nature of these infections, we conducted a retrospective analysis, covering a 3-year period, of patients who were referred to our center with presumed lung cancer but turned out to have pulmonary infection instead. The overwhelming majority of patients (93.3%) referred to "rule out" lung cancer were documented as having a neoplastic process, and only 1.3% had an infection. Fungal infections (histoplasmosis, cryptococcosis, coccidiomycosis) accounted for 46%, mycobacteria for 27%, bacteria for 22%, and parasitic lesions (dirofilariasis) for 5% of these infections. The most common clinical manifestations were cough and chest pain, and the most common radiographic finding was a solitary pulmonary nodule. There were no specific clinical or radiographic features predictive of either infection or neoplastic disease. All patients responded to specific anti-infective therapy with or without surgical excision. Our data indicate that pulmonary infections mimic neoplasms very infrequently. However, establishing a specific diagnosis is critical, since the management and outcome of these two processes are entirely different.