Colloid cyst of the third ventricle: incidental finding indirectly related to death.

Abstract

Introduction: Colloid cysts of the third ventricle are rare, forensic evaluation must determine their relationship with the mechanism of death1. Description of the case: A 30-year-old woman, diabetic, who was admitted due to neurological deterioration and died five days later, an autopsy was performed. Relevant findings: Coronal slices of the brain show severe edema, ventricular obliteration, and evidence of brain death. In the third ventricle there was an ovoid lesion measuring 2.5 x 2.5 x 2cm, with a smooth, light brown surface (Fig. 1-A, marked with an arrow). On cut, the lesion was cystic with dark brown mucosal material (Fig. 1-B). Microscopically, it was lined with cuboidal epithelium (Fig. 2-A). The wall had rupture evidenced by chronic inflammation and cholesterol crystals. The content was eosinophilic, granular material mixed with erythrocytes (Fig. 2-B). Conclusion: Colloid cyst is the intermediate cause of death as it produces obstruction in the circulation of cerebrospinal fluid due to cerebral edema. The direct cause of death was acute pontine infarction due to basilar thrombosis associated with sepsis. The colloid cyst is the direct cause of death when it moves and produces ventricular dilatation with brain herniation, hemorrhage, or enlargement, with the same effects1,2. Reports of its indirect association with the mechanism of death are not common.