Abstract
Tissierella praeacuta, a rare pathogen, was found in a 71-year-old female's internal jugular vein thrombus stemming from sphenoid sinusitis. She presented with lower-extremity weakness, and imaging revealed the thrombus. Subsequent intraoperative cultures identified T. praeacuta. Treatment encompassed intravenous antibiotics and anticoagulation. This case underscores the need to consider unusual pathogens in sinusitis-related thrombosis. To the authors' knowledge, this report is the first documented case of T. praeacuta isolated in sinusitis leading to infectious thrombophlebitis, and it adds to the scarce literature on T. praeacuta infections, emphasizing a multidisciplinary approach for such complex cases.