[Histonet] puzzling morphology

[Walters, Katherine S]

I am once again in need of some collective wisdom from the experts.

I have some paraffin embedded lung tissue in which the bronchial
endothelium cells exhibit "spaces" (around the nucleus) in the cytoplasm
in the H&E 5 micron section.  These were fixed with zinc formalin.

Does anyone know what would cause this absence of tissue?

Thanks again for your wisdom,
Kathy