Fat embolism syndrome represents a life-threatening condition in which blood vessels become clogged by fat droplets coming from fractured parts of the bones seldomly seen in patients with orthopedic trauma. Absence of specific diagnostic criteria and varying degree of presentation symptoms makes it hard to be diagnosed. We present a 20-years-old male injured in road traffic accident as a pedestrian, diagnosed with polytrauma and lethal outcome on the second day of admission. Autopsy and pathohistological findings confirmed death due to damage of important brain centers, as well as signs of massive fat embolism with fat particles found in lungs blood vessels as well as in systemic circulation, suggesting paradoxical embolism throughout exceedingly uncommon pulmonary right to left shunt capillaries, since completely closed heart foramen ovale was also found.