Application of Levanol fast cyanine 5RN stain for demonstrating rhabdomyoblasts in epoxy-embedded tumors.

To facilitate the survey of actomyosin-containing cells in soft tissue sarcomas with skeletal muscle differentiation, the tannic acid-phosphomolybdic acid-Levanol fast cyanine 5RN procedure was applied to plastic-free (deresined) thick sections (2-3 microns) obtained from epoxy blocks conventially prepared for transmission electron microscopy. By light microscopy, rhabdomyoblasts of varying configuration revealed intense dark blue staining reaction. The stained sections were used for orientation and direct interpretation of the ultrastructural material.