A fungal ball within a maxillary sinus with dental root canal filler and rare fungal propagules.

A fungal ball of a maxillary sinus sometimes includes dental treatment-related foreign material because the sinus is close to the root of the upper teeth. We present a case of right maxillary sinus fungal ball with a gutta-percha point, a dental root canal filler. X-ray analysis of the foreign material in the paraffin section of the fungal ball successfully detected zinc, sulfur, and barium, all of which were constituents of the gutta-percha point. The gutta-percha point might have facilitated the formation of the fungal ball through disruption of the sinus-clearing mechanism. Another interesting histological feature of the fungal ball was the finding of calcium oxalate crystals and non-hyphal fungal elements such as cleistothecia, Hülle cells, and conidial heads. This is the first report of such a combination being found in a specimen of human fungal disease. Although fungal culture was not available in the present case, molecular analysis of the formalin-fixed paraffin-embedded tissue of the fungal ball succeeded in revealing only DNA sequences of Aspergillus nidulans and some other environmental Aspergillus spp.