Squamous cell carcinoma is the second most frequent malignant neoplasm of the skin. It is a primary, invasive tumor which appears in areas of the body exposed to the sun, most commonly in the head (nose, ears, chin, lower lip, forehead, temples, cheeks and scalp), neck and hands of the elderly patients.
Squamous cell carcinoma can develop in the presence of an actinic keratosis or other precancerous lesion or even skin area without pre-existing skin lesion (“de novo”). A person’s probability of developing squamous cell carcinoma at some point in his life is estimated to be between 4% and 14%.
The etiological factors involved in the pathogenesis of squamous cell carcinoma include solar radiation, X and gamma radiation, arsenic, polycyclic aromatic hydrocarbons, smoking, chronic inflammation (chronic osteomyelitis), chronic ulcerative scars (Marjolin ulcers), human papillomaviruses (HPV), immunological agents (immunosuppression, transplanted patients) and heredity.