Warthan Dermatology Mohs Skin Cancer Surgery Center. 5913 Virginia Pkwy Ste 300 McKinney, TX 75071 (972) 542-4646. Directions. Warthan Dermatology Mohs Skin Cancer Surgery Center. 5913 Virginia Pkwy Ste 300 McKinney, TX 75071 ... Patient Portal (MyChart) Intranet Login ....