Pulmonary histoplasmosis presenting with the reversed halo sign on high-resolution CT scan.

We describe the case of a 23-year-old man with pulmonary histoplasmosis whose high-resolution CT scan demonstrated the reversed halo sign. We also extensively review the literature about this CT scan sign. The reversed halo sign has been described in a number of diseases, both infectious and noninfectious. However, to our knowledge, this is the first reported case of pulmonary histoplasmosis presenting with this radiologic finding.