Endogenous Activation in Blastomycosis

Abstract

Recent work established the fact that the portal of entry in blastomycosis is the lung. After the initial exposure to the fungus, a pneumonic process develops that may heal spontaneously or progress locally or at distant sites, or both. Frequently, patients present with disseminated disease, while their chest roentgenograms do not show any lesions. Three patients with disseminated blastomycosis with negative chest roentgenograms at the time of diagnosis were seen. Past history showed a pneumonic illness 33, 32 and 4 mo. before diagnosis. Chest roentgenograms from the time of the original illness showed a pneumonic process compatible with blastomycosis in all three. Examination of postbronchoscopy sputa showed the characteristic yeasts of Blastomyces dermatitidis. These 3 patients document for the first time apparent endogenous activation in blastomycosis. A possible explanation for this apparent endogenous activation may reside in the histopathologic similarity between blastomycosis and other chronic granulomatous diseases, especially tuberculosis.