There are seven layers in our skin, all of which consist of different types of cells. The epidermis forms the outermost layer of the skin and visceral organs, is categorized into different forms, like the squamous epithelial layer that forms the external layer. The various types of skin cancer often start in any one of these layers. However, irrespective of the types of skin cancer, diagnosis and treatment should be sought early.

1. Basal cell carcinoma
One of the most common types of skin cancer, basal cell carcinoma can occur anywhere in the body. It occurs in the innermost epidermal layer and has a high chance of recurrence even after getting completely cured in the first diagnosis. The chances of recurrence are mostly high within the first 5 years of the first diagnosis and cure. Any prior history of persistent eczema or other chronic conditions increase the risk for this type of skin cancer.

2. Squamous cell cancer
This is one of the types of skin cancer that has a high number of yearly reports and is staged right after basal cell carcinoma. Though it occurs on the outermost epidermis, it poses a threat of metastasis to the adipose tissue underneath. It requires swift diagnosis and can be cured completely. One of the most common causes of squamous cell cancer is consistent unprotected exposure to UV rays.

3. Merkel cell cancer
Merkel cells are the sensory cells located inside the skin. These cells are directly associated with the nerve endings reaching the brain and spinal cord, i.e., the central nervous system. This is one of the rarest types of skin cancer that affects people with low immunity. Merkel cell cancer mostly affects people above 50 years of age who have consistent exposure to UV rays. Besides, they can quickly undergo metastasis, eventually affecting the brain and spine in severe cases.

4. Melanocyte cell cancer or melanoma
This is one of the most common types of skin cancer that directly affects the melanin-producing cells. The melanin is responsible for the color of the skin and is also credited with the protection from the UV rays of the sun.

5. Rare varieties of skin cancer

• Keratoacanthoma

This is one of the benign types of skin cancer that is mostly diagnosed in the form of tumors, lesions, or outgrowths, which if remains persistent is diagnosed as squamous cell cancer.

• Skin lymphoma

It is one of the rarest types of skin cancer, which affects the lymphoid tissue of the skin and forms tumors.

• Kaposi sarcoma

Directly or indirectly related to the herpes virus, it is diagnosed in HIV patients. This type of skin cancer is also diagnosed as tumors or visible persistent lesions.

• Actinic keratosis

Diagnosed as benign tumors, it can turn into cancer of squamous cells if it is persistent and untreated.