Use of electron microscopy when screening liver biopsies from neonates and infants: experience from a single tertiary children's hospital (1991-2017).

Background: Although the role of electron microscopy is diminishing in several areas of adult pathology, it remains an essential tool for the study of pediatric liver biopsies.Methods: Clinical charts, histologic slides and EM materials of native liver biopsies from patients <1 year old (1991-2017) were reviewed.Results: 677 biopsies were performed on 353 males and 324 females. This study presents the concrete numbers for both the indications and the diseases, and describes the role of EM. EM was performed on 24.7% of liver biopsies and demonstrated key pathologic findings in 10 cases (6%), which led to the appropriate biochemical and/or genetic testing to confirm the diagnoses. The cases included five cases of glycogen storage disease with characteristic findings with cytoplasmic glycogen accumulation, two cases of mitochondrial disorder with pleomorphic mitochondria with crystalloid inclusions and one case each of Niemann-Pick Disease with abundant myelinosomes, Alpha-1 antitrypsin deficiency with deposits in the endoplasmic reticulum and infantile Refsum disease with trilamellar inclusions and lack of peroxisomes. In this study, we describe the detailed histologic and EM findings of each case .Conclusion: EM played an important screening and diagnostic role in the challenging cases and was also used to rule out detectable pathologic conditions.