Studies on intranuclear inclusions and nuclear grooves in papillary thyroid cancer by light, scanning electron and transmission electron microscopy.

OBJECTIVE

To successively examine intranuclear inclusions and nuclear grooves in the same papillary thyroid cancer specimens using a light microscope (LM), scanning electron microscope (SEM) and transmission electron microscope (TEM).

STUDY DESIGN

We stained cells by the Papanicolaou method after fixation in 1.25% glutaraldehyde for LM and then attempted to observe them successively by SEM-TEM after fixation in 2% paraformaldehyde and 2% osmium tetroxide.

RESULTS

On SEM, intranuclear inclusions were observed as elevated parts, like hills, and nuclear grooves were observed as deep fissures or shallow cracks, sometimes with a few in one cell. On TEM, both intranuclear inclusions and nuclear grooves seemed formed by the nuclear membranes. Intranuclear inclusions also possessed cytoplasm and/or cytoplasmic organelles within some expanded areas in the nuclear grooves.

CONCLUSION

It was evident from our three-step technique that intranuclear inclusions and nuclear grooves were essentially the same structures.