The application of lipid-soluble stains in plastic-embedded sections.

The present study was designed to develop a routine method for direct demonstration and precise localization of lipid substances in tissue sections. A panel of lipid-rich tissues was fixed in 4% buffered formaldehyde, infiltrated, and embedded in the water-soluble plastics Technovit 7100, EFL-67, and JB-4. The use of alcohol containing fluids was avoided. Staining with the lipid-soluble dyes Sudan Black B and Oil Red O revealed excellent preservation of tissue lipids in Technovit 7100 embedded sections when compared with cryostat sections of the same tissue specimens. Lipid preservation in EFL-67 and JB-4 embedded sections was inconsistent, even when infiltration and polymerization procedures were performed at 4 degrees C. Combination of lipid-soluble dyes with the periodic acid Schiff, Jones' methenamine silver, or Gomori' reticulin method allowed for an exact localization of lipids in high-quality Technovit 7100 embedded sections. The procedure herein is easily applicable in routine histopathology practice.