Squamous Cell Carcinoma By Gregory L Wells, MD, Ada West Dermatology and Dermatopathology Reviewed / Revised Sep 2022 View Patient Education Symptoms and Signs Diagnosis Prognosis Treatment Prevention Key Points Topic Resources Squamous Cell Carcinoma Squamous Cell Carcinoma... Squamous Cell Carcinoma... Squamous Cell Carcinoma (Lip) Squamous cell carcinoma is a malignant tumor of epidermal keratinocytes that invades the dermis; this cancer usually occurs in sun-exposed areas.