Try mixing equal parts of your alcian blue solution with 3% - 5% 
aqueous silver nitrate.
My guess is the pathologist is looking for "margins".  Alcian blue is 
a help primarily in oreintation during embedding.
By mixing silver nitrate and alcian blue you get the best of both 
worlds.
We dip tissue into the mixture before cut-up (grossing), wherever 
needed and possible.
See what you (and she) thinks and let me know.

It goes gelatinous after a while (dye aggregation).

After dipping, gently blot with a paper towel.
Russ Allison, 
Dental School
Cardiff
Wales