SQUAMOUS CELL CARCINOMA OF THE SKIN
Squamous cell carcinoma is the most common tumor in the sun exposed areas of the body.
The tumor usually appears in older individuals.
The tumor is more common in males than females.
The predisposing factors includes sun exposure due to the ultraviolet irradiation, viruses (HPV), ionizing irradiation, chemotherapy, chemical carcinogens, chronic skin ulcer, draining osteomyelitis, xeroderma pigmentosum, and old burn scars. In the oral cavity, chewing tobacco predisposes to the squamous cell carcinoma.
Grossly, the tumor appears as a red scaling plaque, nodule, or ulcer. The lesion may be associated with hyperkeratosis which in the oral cavity appears as white plaques called leukoplakia.
Microscopically, the tumor may be confined to the epidermis (carcinoma in situ) or may be invasive. The invasive lesions are composed of islands of squamous cells which in well differentiated carcinomas show keratin pearls. Keratin pearls are ball-like structures made of flattened keratinized cells. Squmous cells form intercellular bridges.