Squamous cell carcinoma of the skin is a type of cancer that starts as a growth of cells on the skin. It starts in cells called squamous cells. The squamous cells make up the middle and outer layers of the skin. Squamous cell carcinoma is a common type of skin cancer which is usually not life-threatening. But if it's not treated, squamous cell carcinoma of the skin can grow large or spread to other parts of the body.
It is the 2nd most common form of skin cancer (first is basal cell carcinoma), common in elderly fair-skinned individuals. Major risk factor identified and well-studied is significant sun exposure containing UV rays that damage to keratinocytes and its genetic makeup leading to skin malignancy. Other risk factors are smoking, chewing betel nut, arsenic exposure, old scars or burns etc.
Fig Squamous cell carcinoma
Pathology
With the exposure to the risk factor/ carcinogen there will be genetic alteration that can hamper the cell cycle leading to excessive cell growth and multiplication. This increased & unopposed cell multiplication and decreased cell death lead to tissue growth called carcinoma. With disease progression it can metastasize to nearby organ also.
Fig: Keratin pearl in SCC histology
Presentation:
⦁ Frequently on sun-exposed areas like face (common on lower lips), neck, hands, ears.
⦁ Feature depends on location of the origin.
I.e. Oral SCC: Difficulty chewing, swallowing, Moving Jaw and tongue, Voice changes, weight loss etc.
⦁ Typically, asymptomatic but may be tender especially if ulcerated.
Investigation:
⦁ Diagnosis by skin biopsy that shows atypical keratinocytes and malignant cells that invasion into dermis
⦁ Skin biopsy shows increased mitosis with necrosis and Keratin “pearls” (pathognomic) on histology (Fig:W)
⦁ For staging MRI, CT scan can be done.
Treatment:
⦁ Conservative:
Preventive measure like sun avoidance, sunscreen use.
⦁ Surgical excision of the affected skin can be done.
⦁ Chemotherapy / Radiotherapy.