We congratulate Furuya et al. [1] for their interesting article published in the October 2012 issue of the AJR. In this article they describe a variety of pulmonary conditions that can present with imaging features mimicking those of primary lung cancers. Despite the importance of all the causes mentioned by the authors, we would like to emphasize the relevance of fungal infections as an important cause of pulmonary nodules and masses that can mimic lung cancer, especially in endemic areas. In addition to histoplasmosis, which was well described by Furuya et al., other fungal infections, such as coccidioidomycosis, cryptococcosis, aspergillosis, blastomycosis, and paracoccidioidomycosis can simulate lung malignancy as well [2, 3].

When chest CT shows a solid lesion with irregular margins, malignancy becomes a major possibility followed by other potential diagnoses according epidemiologic, clinical, and laboratory correlation [4]. We report another type of pulmonary fungal infection in an immunocompetent patient. This infection was initially misdiagnosed because of the radiologic similarity with a pulmonary neoplasm (Fig. 1).

The inclusion of fungal infection in the differential diagnosis usually occurs when different tests for malignancy remain negative or when treatment of the most common infections is not successful. Rolston et al. [2] studied 2908 patients who underwent lung biopsy due to lung lesions suspicious for malignancy. In 37 (1.3%) cases, the final diagnosis was infection, and fungi were the most common pathogen, accounting for 46% of the diagnostics [2].

Even in patients presenting with clinical and radiologic findings suspicious for malignancy, radiologists should be aware of other diagnoses, including fungal infections. Because the therapeutic planning and outcomes are quite different from malignancy, early recognition of pulmonary fungal disease is essential to provide adequate therapy.