Skin Cancer


The skin not just protects the body against light, heat, cold, injury and infection but also acts a source for storage of fat, water and vitamin D. It is made up of two main layers and numerous types of cells. The two layers are dermis (inner layer) and epidermis (outer layer).

The upper layer of skin, epidermis, contains three different types of cells – Squamous cells, Basal cells and Melanocytes. Skin cancer is a medical disorder in which malignant cells (cancer cells) develop on the epidermis.

Skin cancer affects more than 1 million people each year. It is caused due to various reasons with exposure to sun’s UV rays as the most cause. Though skin cancer is the most common type of cancer, it is not as fatal when compared to other types of cancers like those affecting lungs, pancreas, breasts, prostate and stomach.

Common Types of Skin Cancer

Though there are different types of skin cancer, three of these are most common namely:

  • Squamous cell carcinoma
  • Basal cell carcinoma
  • Melanoma

Squamous Cell Carcinoma

What is Squamous Cell Carcinoma ?

Squamous cell carcinoma begins in the thin and flat squamous cells that look similar to fish scales when viewed under a microscope. This explains the derivation of the word ‘squamous’ from the Latin word ‘squama’ which refers to ‘scale of either a fish or serpent’. These cells are present in the tissues on the surface of skin, linings of various hollow organs and the routes of digestive and respiratory tracts.

Squamous cell carcinoma is a type of non-melanoma skin cancer usually affecting the skin overexposed to UV rays. The skin on face, mouth, lips, hands, legs, back and neck are the most effected parts.

It is distinguished by a red, scaly or crusted patch on skin, a firm red nodule or an ulcer that won’t heal. The tumor grows slowly and sometimes bleeds intermittently. The tumor is similar to a hard plaque has opalescent quality. The skin is photo-damaged with the presence of numerous solar keratoses or actinic keratoses.

The early detection and the right treatment can cure squamous cell carcinoma. If left untreated, it invades and usually destroys a large part or the entire tissues surrounding the tumor leading to disfiguring.

Some types of squamous cell carcinomas can be aggressive, especially those found on lip or ear. These types of aggressive carcinomas on being ignored can spread to the internal organs, lymph nodes, nerve routes and bloodstream.

Squamous Cell Carcinoma Diagnosis

Squamous cell carcinoma can be diagnosed by a biopsy involving the examination of small amounts of tissue using a microscope. The subcutaneous tissues and basalar epithelium should be studied for correct diagnosis. Sometimes, a punch or incisional biopsy is also preferred. A detailed biopsy to the subcutaneous tissue or the dermis usually reveals the presence or absence of cancer accurately.

Squamous cell carcinoma Pictures

Picture 1 : Squamous cell carcinoma

Image source : atlasdermatologico

Picture 2 : Squamous cell carcinoma

Image source : atlasdermatologico

Picture 3 : Squamous cell carcinoma

Image source : atlasdermatologico

Squamous Cell Carcinoma Treatment

Once diagnosed, there are various surgical and non-surgical options for treatment of squamous cell carcinoma. The dermatologist determines the proper treatment only after studying various factors like location of tumor, size, patient’s health and the microscopic characteristics of the tumor.

Most of the treatments are minor and involve some local anesthesia. These include simple surgical excision, mohs micrographic surgery, radiation therapy, cryosurgery, electrodesiccation and curettage. Medications like imiquimod and 5-fluorouracil are used as part of the topical therapy and can be used at home for treating squamous cell carcinoma.

Basal Cell Carcinoma

What is Basal Cell Carcinoma ?

Basal cell carcinoma affects the basal cells present in stratum basale, the bottom-most layer of the epidermis. Exposure to UV rays is the major cause among various others for basal cell cancer.

Basal cell carcinoma is the most common one among the various types of skin cancer. It accounts for more than 75 percent of the diagnosed cases of skin cancer. It is most commonly seen in people with fair skin, blond or red hair, weak immune system and exposure to coal tar, creosote, arsenic or pitch. Those who underwent radiation therapy are also at higher risk of developing basal cell carcinoma. The risk of basal cell cancer increases with age.

Basal cell carcinomas are further divided into diverse types based on factors like location, appearance and severity like nodular, micro nodular, cystic, infiltrative, superficial, and pigmented, polypoid, pore-like and aberrant basal cell carcinomas.

The basal cell cancers grow slowly and do not spread to other organs except in some rare cases. This makes the carcinoma treatable and less fatal. The cancer gains access to the surrounding area and partially damage or permanently destroy the tissues instead of traveling in blood stream or metastasize. Therefore, such a type of cancer should be treated at the earliest.

Basal cell carcinoma appears in different shapes and sizes. Most often it looks like small, pimple-like, dome-shaped growth with a pearly color. The blood vessels may be visible on its surface. The sores formed usually bleed and a red area causes irritation.

Basal Cell Carcinoma Diagnosis

Similar to a squamous cell carcinoma, basal cell carcinoma is also diagnosed by a biopsy. The affected area is numbed and tissues are collected from the suspected lesion. These tissues are examined under a microscope for any presence of cancer.

Basal cell carcinoma Pictures

Picture 4 : Basal cell carcinoma under left eye

Image source : atlasdermatologico

Picture 5 : Basal cell carcinoma  (with tiny vessels under the surface)

Image source : atlasdermatologico

Picture 6 : Basal cell carcinoma

Image source : atlasdermatologico

Basal Cell Carcinoma Treatment

The appropriate treatment for basal cell cancer depends on the various factors similar to squamous cell carcinoma. The various types of treatments include simple surgical excision, electrodessication and curettage, cryosurgery, mohs micrographic surgery, radiation therapy, laser surgery and radiation therapy. Topical therapy and photodynamic therapy are also suggested according to the severity of the cancer.

Malignant Melanoma

What is Malignant Melanoma ?

Malignant melanoma is the most fatal type of skin cancer that can develop on any part of the skin. The legs, arms and trunk are however, the most commonly affected areas. An early detection of this cancer is possible and also easily treatable.

Melanocytes are the cells that give color to skin, hair and eye. When these are cells are damaged, they grow uncontrollably leading to melanoma. It starts on the skin’s surface and grows deeper into the skin. It turns life-threatening on reaching further deep to the blood and lymphatic vessels.

Though the causes for development of malignant melanoma are not clear, exposure to UV radiations is certainly an important factor. Fair-skinned people are more prone to melanoma. People with more moles on their body are also at higher risk of developing melanoma.

They symptoms of melanoma include a mole or freckle changing color, size or shape. It has an irregular outline and more than one color is possible.

Malignant Melanoma Diagnosis

Diagnosis of melanoma can be done by a biopsy involving the tissues from the affected areas. Before the collection of the tissues, the area is numbed and if infected, the tissues show melanoma cells under a microscope. To determine the stage of melanoma, various imaging techniques including x-ray, ultrasound, CT scan, MRI, radio-isotopic scan of bone or organ and PET scan are recommended.

Malignant Melanoma Pictures

Picture 7 : Malignant melanoma photo

Image source : atlasdermatologico

Picture 8. Melanoma – appearing partly as flat nevus and partly as nodular growth

Image source :

Picture 9 . Melanoma on the back

Image source : atlasdermatologico

Malignant Melanoma Treatment

Treatment of melanoma starts with removing melanoma and some surrounding normal skin (as a cautious measure) by means of surgery. The treatment depends on the stage of the condition. These include sentinel lymph node biopsy, immunotherapy, chemotherapy, clinical trials or radiation therapy. If the melanoma reaches an advanced stage, a combination of these treatments is used.

Rare Types of Skin Cancer

Apart from the three common types of skin cancers, there are few other rare types. These include the following:

Sebaceus gland carcinoma

often affects the old people on their eyelids.

Kaposi’s sarcoma

red, brown and purple nodules appearing on the skin. Usually associated with organ transplants and AIDS.

Spindle cell tumors

Atypical fibroxanthoma – Caused due to severe exposure to UV rays leading to dome-shaped red nodules that grow rapidly or turn into ulcers.

Dermatofibrosarcoma protuberans

This skin tumor affects the dermis layer. Irregular red or violet plaques are observed which can be removed only by surgery.

Anogenital carcinoma

Anogenital carcinoma affects the penis, vulva, anus, per-anal skin and the scrotum.

Paget’s breast disease

Paget’s breast disease affects the breast nipples in women. The nipple turns red and itchy. In some rare cases, it affects the men too.

Cutaneous lymphoma

Cutaneous lymphoma affects the lymphocytes in skin.

Merkel cell carcinoma

Merkel cell carcinoma appears as red or violet bumps on the skin and affects the neuroendocrine merkel cells.


Angiosarcoma caused by disorders in skin blood vessels.


Leimyosarcoma is a rarely reported skin cancer that arises from muscle cells.

Microcystic adnexal carcinoma

Microcystic adnexal carcinoma arises from the sweat glands present on the skin. It is distinguished by the development of red or yellow plaque on head or neck.

Pre-cancerous Skin Growths

Certain types of skin changes increase the chances of developing skin cancer at a later stage. The common type of pre-cancerous skin growths are:

Actinic keratosis

It is a rough spot on the skin noticed due to overexposure to the sun. This can lead to squamous cell carcinoma. However, the process of developing skin cancer due to this change is rather slow and takes years. The most commonly affected body parts are the face, neck, upper chest, scalp, back of hand and forearms. These rough spots can be treated by cutting them off or undergoing a cryosurgery to completely terminate the process of developing squamous cell carcinoma.

Actinic cheilitis

It is a type of inflammation and skin growth which closely resembles actinic keratosis. It affects the lips leading to whitish discoloration. Painless but persistant lesions are formed on the lips due to various factors like overexposure to sun, tobacco, poor hygiene and lip irritation.

Non-cancerous Skin Growths

There are certain skin growths that are wrongly believed by most people to be either characteristics of skin cancer or conditions that may lead to skin cancer. Such misleads are generally associated with the following skin growths that are not cancers:

  • Anal and genital warts
  • Birthmarks, beauty marks or beauty spots.
  • Moles are also considered by most people as the signs of developing skin cancer. Moles are seen on the increase of melanin in body and are not related to skin cancer. However, moles that change in size and appearance sometimes indicate the developing of skin cancer.
  • Moluscum contagiousum, a disease which is characterized by the appearance of dome-shaped, flesh-toned papules scattered in various parts of the body.


Skin Cancer – Keyvan Nouri, McGraw-Hill Publications.


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