A significant lifetime ultraviolet radiation exposure is the principal determinant of squamous cell carcinoma (SCC) and the disease appears most frequently in the older, fair-skinned population [1]. Increased use of natural or artificial sunlight by the younger generation may be one of the reasons for the rising incidence of cutaneous squamous cell carcinoma (cSCC) [2] [3]. Chronic skin ulceration and an immunosuppressed state are also predisposing factors for this malignant disease.

The carcinoma appears most commonly on sun-exposed areas, mainly on the head and neck. Changes are often present on the forehead, scalp, lip, and ears. The presentation is variable and the tumor could arise in the form of a plaque, nodule, or non-healing ulcer with scaling and crusting. The size is an important indicator for the risk of metastasis, as is the rate of growth and the state of differentiation of the cells. Growths larger than 2 cm metastasize more frequently than smaller ones [4] [5]. Another factor influencing the rate of metastases is the location with the lips and ears among the most dangerous areas.

There are several forms of cSCC, which may range from in situ neoplasm to metastatic disease. Cutaneous SCC often develops from actinic keratoses which are very common, scaly and small precancerous lesions found on sun-exposed areas [6]. Different studies report varying rates for actinic keratoses turning into invasive cSCC, while about a quarter of them will regress within a year [7]. Actinic cheilitis, another precancerous lesion, appears on a lip as a fissure or dry patch, and sometimes develops into SCC. Squamous cell carcinoma in situ, in some cases called Bowen disease, is a precursor of fully developed cSCC. Invasive cSCC could spread locally and metastasize [4]. The variant of SCC, Marjolin ulcer, can develop at the sites of chronic inflammation and has an over 30% metastasis and mortality rate [8] [9] [10].

Conjunctival squamous cell carcinoma has a variable appearance. An unusual pterygium may indicate the presence of a tumor, hence all resected pterygia should undergo histologic examination [11].

A careful description of the appearance, location, and size of the tumor is essential. The gold standard for diagnosis is the histological evaluation. This method efficiently distinguishes cSCC from other skin conditions [12]. Nevertheless, problems do arise, especially when the bioptic sample is too small [13]. The biopsy must contain the full thickness of the diseased tissue, as well as adjacent normal skin for comparison. Excisional biopsy may be well suited for small lesions, but for larger lesions and those in esthetically and functionally important areas, incisional biopsy is performed as a base for a decision of definitive treatment.

Actinic keratosis contains atypical keratinocytes. It is classified according to the distribution of the atypical cells. In the first category (KIN I), the dysplastic keratinocytes are restricted to the lower third of the epidermis, whereas in higher categories they occupy an increasing thickness. In the KIN III category – which is the same as cSCC in situ - the atypical keratinocytes occupy all layers of the epidermis [14].

The classification of cSCC is according to the tumor-node-metastasis (TNM) staging system. This scheme incorporates the size of the tumor, the involvement of regional lymph nodes, and the absence or presence of metastases. An alternative scheme for nodal staging has been developed recently with good predictive power [15].

New methods for a noninvasive examination of skin lesions (dermoscopy, reflectance confocal microscopy, optical coherence tomography) have been developed [16]. Computerized tomography (CT) and magnetic resonance imaging (MRI) are used to examine the extent of the disease.

Treatment for SCC depends on the size, location, and stage of the cancer. Common treatments include:

• Surgical Excision: Removing the cancerous tissue along with some surrounding healthy tissue.
• Mohs Surgery: A precise surgical technique where layers of cancer-containing skin are progressively removed and examined until only cancer-free tissue remains.
• Cryotherapy: Freezing the cancer cells with liquid nitrogen.
• Radiation Therapy: Using high-energy rays to target and kill cancer cells.
• Topical Treatments: Applying medicated creams or ointments directly to the skin.

The prognosis for SCC is generally favorable, especially when detected and treated early. Most cases can be cured with appropriate treatment. However, if left untreated, SCC can grow larger and spread to other parts of the body, making it more difficult to treat. Regular follow-up is important to monitor for any recurrence or new lesions.

The primary cause of SCC is prolonged exposure to UV radiation, which can damage the DNA in skin cells. Other risk factors include having fair skin, a history of sunburns, a weakened immune system, exposure to certain chemicals, and a history of precancerous skin lesions or other skin cancers.

SCC is one of the most common types of skin cancer, with millions of cases diagnosed worldwide each year. It is more prevalent in older adults, particularly those with fair skin and a history of significant sun exposure. Men are slightly more likely to develop SCC than women.

SCC develops when the squamous cells in the epidermis undergo genetic mutations, often due to UV radiation. These mutations cause the cells to grow uncontrollably, forming a tumor. If not treated, the cancer can invade deeper layers of the skin and spread to other parts of the body.

Preventing SCC involves minimizing UV exposure. This can be achieved by wearing protective clothing, using broad-spectrum sunscreen with an SPF of 30 or higher, seeking shade during peak sun hours, and avoiding tanning beds. Regular skin checks can help detect early changes that may indicate SCC.

Squamous Cell Carcinoma of the skin is a common and potentially serious form of skin cancer caused primarily by UV exposure. It presents as a persistent, scaly lesion and is diagnosed through a biopsy. Treatment options are effective, especially when the cancer is caught early. Preventive measures focus on reducing UV exposure and monitoring skin changes.

If you notice any new or changing skin lesions, especially those that do not heal, it is important to seek medical evaluation. Early detection and treatment of SCC can lead to a high cure rate. Protecting your skin from the sun and performing regular self-examinations can help prevent SCC and other skin cancers.

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