Pneumosinus Dilatans frontalis: a case of incidental autopsy diagnosis.

Pneumosinus Dilatans Frontalis (PDF) is a rare pathologic condition characterized by expansion and hyper aeration of the frontal sinuses. This abnormality has been described in otolaryngology, ophthalmology, neurology, and radiology journals, while only a few autopsy studies are reported in the English literature. The etiology of this condition remains unclear, although multiple theories have been proposed. Clinically, PDF is often an asymptomatic condition, but it can lead to significant bone deformation with esthetic complaints, and even severe associated neurological deficits. In the following case report, a 20-year-old Caucasian male committed suicide by asphyxia due to plastic bag suffocation combined with a vitiated atmosphere as a consequence of helium inhalation. At postmortem an abnormal expansion of the frontal sinuses was detected, involving the frontal bone just above the orbits. The defect showed a multiloculated appearance in the sinus cavities. An incidental diagnosis of PDF was made. A description of the findings and a hypothesis of the clinical relevance of PDF in the reported case are presented.