We observed and treated mycosis affecting an extensive area of the paranasal sinuses. A 63-year-old woman was referred to our hospital because of left cheek swelling. Both maxillary sinuses were cloudy on X-ray examination. CT examination showed a low density area that included high density areas in both maxillary sinuses and the left ethmoid sinus. After these examinations, we diagnosed this case as bilateral maxillary and left ethmoid sinusitis dentalis with suspected mycosis. Surgery was performed under general anesthesia. Histological examination revealed fungi. Fungi were detected in culture specimens and identified as Aspergillus. At the same time, oral indigenous bacteria closely related to odontogenic infections, i.e., Streptococcus constellatus, Peptostreptococcus anaerobius, Prevotella intermedia, and Prevotella sp., were isolated for anaerobic culture. Clinically and microbiologically, these results suggest that this case was caused first by odontogenic infection, followed by the adherence and proliferation of Aspergillus.
