Sheet plastination of the larynx for whole-organ histology.

Abstract

Whole organ serial sections of the larynx are recognized to improve the assessment of laryngeal pathology. The human larynx with its complex anatomy of different types of tissue with their marked differences in hardness complicate the cutting process. The methods established are either very costly, time consuming and prone to artefacts, or sections are too thick for a histological work-up. Prior decalcification causes major shrinkage, thus morphometry is not feasible. We describe a technique of sheet plastination to produce whole-organ sections which allows a full-scale histological investigation without prior decalcification. Deep-frozen larynges are cut into 4-micron-thick sections using an ordinary slicing machine. Slices are dehydrated in acetone and plastinated in Biodur E50/E7/ AE10/E700. These specimens are cut into sections of about 80 microns thickness using a diamond-wire saw. An ultra-milling device reduces the section thickness down to about 10 microns. Surface staining of different kinds like Richardson, methylene blue or Paragon yields sufficient contrast for exact diagnosis. Deplastination and consecutive paraffin-like staining is possible, but results are not yet fully satisfying. Histological sheet plastination produces almost artefact- and shrinkage-free whole-organ sections in a period of about 1 week. The technique is useful for studies of micromorphometry or tumor spread. Theoretically, application of immunohistochemical staining methods seems to be possible. This might lead to mapping the proliferation activity of laryngeal cancer as it is presented on whole-organ sections.