Source : Webster's Revised Unabridged Dictionary (1913)

Histologic \His`to*log"ic\, Histological \His`to*log"ic*al\ a.
   (Biol.)
   Pertaining to histology, or to the microscopic structure of
   the tissues of living organisms. -- {His`to*log"ic*al*ly},
   adv.

Source : WordNet®

histologically
     adv : involving the use of histology or histological techniques;
           "histologically identifiable structures"