Histologic Artifacts of Autolytic Müller Cell Foot Process Swelling in Postmortem Examination of Infant Eyes: Potential Pitfall in the Evaluation of Traumatic Retinal Hemorrhages.

IMPORTANCE Retinal hemorrhages are an important sequela of fatal head trauma. The accurate pathologic diagnosis of retinal hemorrhages has critical implications for determination of the manner of death. OBSERVATIONS We describe an autolytic postmortem histologic artifact of eosinophilic Müller cell foot process swelling that mimics a nerve fiber layer hemorrhage. From April 24, 2012, through November 11, 2014, we conducted postmortem examination of the eyes of 23 infants and children who were referred to our institution for possible nonaccidental head trauma. A focal artifact of Müller cell foot process swelling was identified in most patients (16 of 23) up to 4 years of age. Three infants, all of whom were younger than 3 months, demonstrated diffusely swollen Müller cell foot processes with intensely eosinophilic cytoplasm that mimicked erythrocytes of nerve fiber layer hemorrhages. The difference in the mean age between patients with diffuse eosinophilic artifacts (1.7 months) and patients with only a multifocal, focal, or absent artifact (13.3 months) was 11.6 months (95% CI, 6.5-16.7 months). Glycophorin C immunohistochemical analysis was useful to differentiate this artifact from nerve fiber layer hemorrhage. CONCLUSIONS AND RELEVANCE Our case review demonstrates an artifact of eosinophilic Müller cell foot processes swelling in postmortem examination of young infant eyes, a potential pitfall in the diagnosis of retinal hemorrhages. Our findings have important implications for the diagnosis of retinal hemorrhages in potential cases of nonaccidental head injury.