Sino-Orbital Fungal Infection by Tilletiopsis minor, a Rare Human Pathogen, Diagnosed by Internal Transcribed Spacer Sequencing.

Orbital infection can be caused by numerous pathogens, and accurate diagnosis informs appropriate therapy. The authors report a case of a 78-year-old man with well-controlled diabetes mellitus and recurrent sino-orbital infection following multiple surgical procedures with negative microbiologic results. This case presented a diagnostic and treatment challenge and was aided by the use of internal transcribed spacer sequencing for pathogen identification. The fungal pathogen, Tilletiopsis minor, has not previously been described as a human pathogen in the sinus and orbit. This report describes a novel orbital pathogen and highlights the importance of diagnostic diligence and utilizing internal transcribed spacer sequencing in the workup of atypical orbital infection.