Comparison in Quantities from Including Angles Comprising Lines of Hypha Themselves in Histological Images between Mucorales and Aspergillus: An Exploration into Basic Algorithm Supporting Future Automated Histological Image Analyzing System to Isolate Mucorales from Other Filamentous Fungi

Background: The rate of aspergillosis has decreased due to improvements in therapy. The rate of mucormycosis, however, has gradually increased in recent years. Both aspergillosis and mucormycosis produce histologically similar hyphae, pointing to the need for an objective tool to distinguish between them. Methods: Three aspergillosis cases and three mucormycosis cases were selected from autopsy cases in our hospital. Representative histological images were captured and hyphal angles in extravascular and intravascular lesions were calculated. Results: For both extravascular and intravascular lesions, the average hyphal angle of aspergillosis was acute, and the standard deviation was less than that of mucormycosis. In aspergillosis, the average hyphal angle for extravascular lesions was acute, and the standard deviation was less than that for intravascular lesions. However, for mucormycosis, there was no significant difference in both the average and standard deviation of the hyphal angles. Conclusion: Surgical pathologists should carefully examine the histological characteristics of the fungus to correctly identify specimens and be able to administer proper therapies.