LAUSR

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.