Yuetian Chen asks about doing a Fontana-Masson silver stain on an appendix:

What you're looking for is argentaffin (enterochromaffin) granules in 
specialized cells. These granules are quite stable after adequate 
formaldehyde fixation, and will resist alcohol extraction before or after 
staining, as well as ordinary paraffin processing.

If the appendix is poorly preserved (prolonged delay before fixation, or 
inadequate fixation) the granules may not stain well, and for the HTL 
examination you would then need to find another specimen.

I am fairly sure that the stain does not work on frozen sections.

Bob Richmond
Samurai Pathologist
Knoxville TN