Vinod Khanijow¹, Sinead McCarthy^1
1Northern Forensic Pathology Service, Auckland City Hospital, Auckland, New Zealand

Thromboembolism in transit is a rare but potentially fatal condition often associated with pulmonary embolism. We report the case of a 59-year-old woman who experienced a witnessed collapse at home following two weeks of breathlessness. Post-mortem examination revealed a saddle pulmonary embolus within the pulmonary trunk and a thromboembolism in transit traversing a patent foramen ovale (PFO). Notably, no thrombus was identified in the lower extremity or pelvic deep veins, which, in the presence of an intracardiac shunt, suggests a paradoxical systemic embolus. Mortality rates for thromboembolism in transit are high, reaching up to 45%, and optimal treatment strategies remain uncertain. This case underscores the importance of considering an intracardiac communication, such as a PFO, in cases of unexplained arterial circulation embolism.