Tissue expansion of lung bronchi due to tissue processing for histology – A comparative analysis of paraffin versus frozen sections in a pig model

• Published in: Pathology, research and practice research and practice, 2019-07, Vol.215 (7), p.152396-152396, Article 152396
• Main Authors: Schmitt, Volker H., Schmitt, Christine, Hollemann, David, Weinheimer, Oliver, Mamilos, Andreas, Kirkpatrick, C. James, Brochhausen, Christoph
• Format: Article
• Language: English
• Subjects: Animals; Bronchi - pathology; Frozen Sections; Lung - pathology; Lung bronchi; Paraffin Embedding; Paraffin sections; Specimen Handling - methods; Swine; Tissue fixation; Tissue processing; Tissue shrinking
• ISSN: 0344-0338; 1618-0631
• DOI: 10.1016/j.prp.2019.03.024

Tissue shrinking due to fixation and processing is well known. However, the degree of shrinking varies significantly with the tissue type as well as the processing method and is not well studied in various tissues. In daily pathological routine workflow, histological specimens from frozen and paraffin sections are performed from the same tissue. In the present study we compared the thickness of bronchus walls obtained from paraffin and frozen sections. Pig lungs were frozen in ventilated condition in liquid nitrogen and 36 bronchi were isolated after dissection. Frozen sections of 5 μm thickness were performed and the remaining tissue was fixed and embedded in paraffin after fixation in 4% formalin. Frozen and paraffin sections from the same cutting edge were analysed after haematoxylin and eosin staining by measuring the wall thickness of the bronchi using high power fields of 400-fold magnification. In each bronchus 40 measurements were implemented at different wall positions distributed over the entire wall area. Summed up, in each group 1440 wall measurements were performed in total. Statistical analysis was conducted using the Wilcoxon test and t-test as well as Pearson’s correlation coefficient with a significance level at P