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Restylane (Q-Med, Uppsala, Sweden), a hyaluronic acid (HA) that is microbiologically produced and then cross-linked, is becoming popular as a dermal filler for improvement of facial lines and wrinkles. However, it is currently believed that the clinical and histologic persistence of this filler is from 6 to 9 months. We recently encountered Restylane in tissue where it had been implanted 23 months prior to removal of a basal cell carcinoma (BCC) on the lip, and its presence caused some confusion with HA that surrounds BCC nests.To show and to contrast the histologic dermal appearance of Restylane and its metachromatic staining characteristics with toluidine blue from those of HA that surrounds BCC nests.Toluidine blue staining at pH 7.07 was performed on excised tissue containing Restylane and BCC on the upper lip.Restylane appeared as reddish-purple amorphous masses, whereas the HA that frames BCC nests appeared redder and more well defined.The amorphous metachromatic reddish-purple color staining of Restylane with toluidine blue is due to its HA content. This staining pattern should be differentiated from the well-defined red color of HA that normally borders BCC nests. Restylane may persist in the dermis as long as 23 months after implantation.