Dear Bill (Sinai),
Terry's comments on Tzanc cells are appropriate, as you would 
expect.  Most commonly, Tzanc cells are considered a useful 
indicator of  pemphigus vulgaris in the differential diagnosis of 
bullous lesions.  Immunofluorescence is the indicator of choice.
However, Tzanc cells can be seen and identified in lesion smears, 
but usually only if an intact bulla is broken to prepare the smear 
and the base of the lesion is sampled.  They are quite 
characteristic and easily recognised.  Suggest looking at a good 
dermatology or oral pathology text-book to see pictures.  Then you 
will know them when you see them!

There is no "stain" for them - haematoxylin is as good as any and 
better than most - change that, best of all!
Russ Allison, 
Dental School
Cardiff
Wales