Background: Expression of immersion syndrome implies sudden and unexpected death of swimmer in water. A drowned swimmer is still a riddle for the forensic and clinical doctors. Pathophysiological mechanisms which cause immersion syndrome may be divided into vegetatively regulating and mechanical ones.
Case report: We presented heterotopic intracranial ossification with the anomaly of the skull base bones development in a young man, a swimmer, drowned after entering water and where the circumstances required expertise in forensic medicine.
Conclusion: Intracranial heterotopic ossification with or without a disorder in the development of skull bones may be one of the causes of immersion syndrome.