Basal cell carcinoma is a type of non-melanoma skin cancer. It gets its name because it arises from the basal cells, which are located in the lowest layer of the epidermis (the outermost layer of our skin). The primary job of the basal cell layer is to act as a “nursery,” constantly producing new skin cells that migrate upward to replace the older cells that are shed from the surface.

The core problem in BCC is damage to the DNA within these basal cells, which causes them to lose their normal growth controls.

• A helpful analogy is to think of the basal cell layer of your skin as this cellular nursery, where the DNA in each cell is the “blueprint” that tells it when to divide and, just as importantly, when to stop.
• Ultraviolet (UV) radiation from the sun is like a persistent “computer virus” that attacks and corrupts this blueprint over many years.
• With enough cumulative sun exposure, this virus can cause enough damage to the blueprint that the “stop dividing” instruction is effectively deleted.
• The basal cells then begin to multiply uncontrollably, forming a disorganized, cancerous growth.
• However, these are “homebody” cancer cells. They are very good at slowly invading their local neighborhood (the surrounding skin tissue), but they are extremely bad at traveling to distant cities (metastasizing to other organs). This is why the condition is so highly curable.

In my experience, many patients are surprised to hear they have skin cancer because their lesions looked harmless, often just a small bump that wouldn’t heal.

The cause of almost all basal cell carcinomas is DNA mutations in the basal cells that are induced by long-term, cumulative exposure to ultraviolet (UV) radiation.

This UV radiation comes primarily from two sources:

1. Sunlight: The main source of UV exposure for most people.
2. Artificial Tanning Beds: These emit concentrated UV radiation and are a major risk factor for all types of skin cancer.

The UV radiation damages specific tumor suppressor genes within the basal cells, most notably genes that are part of a cellular signaling pathway known as the Hedgehog pathway. This damage allows the cells to grow and divide without the normal checks and balances.

In my experience, I’ve seen it more frequently in fair-skinned individuals, especially those with a history of sunburns or who spend a lot of time outdoors without sun protection.

A person develops BCC from a combination of their genetic predisposition (their skin type) and their lifetime environmental exposure to UV radiation. It is not contagious.

The most important risk factors include:

• Chronic Sun Exposure: This is the most significant risk factor. A person’s total, cumulative sun exposure over their lifetime is the primary driver of risk.
• Fair Skin Type: Individuals with fair skin that burns easily, light-colored eyes (blue or green), and blond or red hair (Fitzpatrick skin types I and II) are at the highest risk. People with darker skin tones have more natural melanin, which provides some protection, but they can still develop BCC.
• History of Sunburns: Having one or more blistering sunburns, especially during childhood or adolescence, significantly increases the risk later in life.
• Age: Because sun exposure is cumulative, the risk increases with age. BCC is most common in people over the age of 50.
• A Personal or Family History of Skin Cancer: If you have had one BCC, you are at a higher risk of developing another. Having a family history also increases your risk.
• A Weakened Immune System: Individuals with a compromised immune system, such as organ transplant recipients on immunosuppressive drugs, are at a much higher risk.
• Other Exposures: Rare risk factors include exposure to arsenic or therapeutic radiation.

In my experience, it often develops in sun-exposed areas like the face, neck, and arms, particularly in people with cumulative sun exposure over many years.

BCC is a master of disguise and can look like a harmless pimple, scar, or sore. The key is that it is a lesion that persists and does not heal. It most often develops on sun-exposed areas of the body, such as the face, scalp, ears, neck, shoulders, and back.

There are five common signs and appearances of basal cell carcinoma:

1. A Pearly or Waxy Bump: This is the most classic presentation. It is a dome-shaped, pearly or skin-colored bump that is often translucent, meaning you can sometimes see tiny, superficial blood vessels (telangiectasias) on its surface.
2. A Non-Healing Sore: A sore that bleeds, oozes, or crusts over, seems to heal, and then reappears. A common patient story is, “I thought it was a pimple that I picked, but it just won’t go away.”
3. A Pinkish or Reddish Patch: A flat, slightly scaly, pinkish patch of skin, which can sometimes be mistaken for a patch of eczema or psoriasis.
4. A Scar-like Lesion: A flat, firm, waxy, and ill-defined scar-like area. The color may be white or yellow. This “morpheaform” type can be more aggressive as its borders are difficult to see.
5. A Pigmented Lesion: Less commonly, a BCC can contain melanin and appear as a brown, blue, or black lesion, which can be mistaken for a mole or a melanoma.

Clinically, I look for rolled edges, visible blood vessels (telangiectasia), or ulceration in the lesion, which are hallmark signs of BCC.

A diagnosis of BCC is first suspected by a dermatologist during a clinical skin examination and is then confirmed with a skin biopsy.

• Clinical Examination: A dermatologist will examine your skin, often using a handheld magnifying instrument called a dermatoscope, which allows them to see features of the lesion that are not visible to the naked eye. The appearance of the lesion will often be highly suggestive of a BCC.
• Skin Biopsy: A biopsy is the only way to definitively confirm a diagnosis of skin cancer. This is a simple and quick procedure performed in the doctor’s office under local anesthesia. The most common type is a shave biopsy, where the doctor uses a small blade to shave off the top layers of the suspicious lesion.
• Pathology: The tissue sample is sent to a laboratory where a dermatopathologist examines it under a microscope. The pathologist can see the characteristic nests of basaloid cells, confirming the diagnosis of BCC. The pathology report will also often identify the subtype of the BCC (e.g., nodular, superficial, morpheaform), which can help to guide treatment.

In my experience, dermoscopy can help distinguish BCC from benign skin lesions before biopsy, especially in early or subtle cases.

The good news is that there are many highly effective treatments for basal cell carcinoma, and the cure rate is extremely high, exceeding 95% for most primary tumors. The goal of treatment is to completely remove the cancer while preserving as much of the surrounding healthy tissue as possible to achieve the best cosmetic outcome.

The choice of treatment depends on the size, location, and subtype of the BCC.

1. Mohs Micrographic Surgery

This is considered the gold standard for treating BCCs located in cosmetically sensitive or critical areas, such as the face, ears, hands, and feet, as well as for large, recurrent, or aggressive subtypes.

• Procedure: Mohs surgery is a specialized technique performed by a fellowship-trained Mohs surgeon. The surgeon removes the visible tumor one thin layer at a time. Each layer is immediately processed into a slide in an on-site lab and examined by the surgeon under a microscope. The surgeon is able to create a “map” of the cancer. If any cancer cells are seen at the edge of a layer, the surgeon knows exactly where to go back and remove another thin layer, only from that specific spot. This process is repeated until no cancer cells remain.
• Advantage: This method ensures the complete removal of all the cancer “roots” while sparing the maximum amount of healthy tissue, leading to the highest possible cure rate and the smallest possible scar.

2. Surgical Excision

For straightforward BCCs on less cosmetically sensitive areas like the trunk or limbs, a standard surgical excision is often performed. The dermatologist or surgeon cuts out the visible tumor along with a small margin of surrounding healthy skin and sends the entire specimen to a lab for a pathologist to confirm that the margins are clear.

3. Electrodessication and Curettage (ED&C)

This is a simple office-based procedure often used for small, superficial BCCs on the trunk or limbs. The doctor uses a sharp, spoon-shaped instrument (a curette) to scrape away the cancerous tissue, and then uses an electric needle to cauterize the base.

4. Topical Therapies

For very superficial BCCs, certain prescription creams can be used. These include imiquimod, which stimulates the immune system to attack the cancer cells, and 5-fluorouracil, a topical chemotherapy agent.

5. Radiation Therapy

Radiation is a good option for patients who are not good candidates for surgery. It involves delivering a series of focused, high-energy beams to the tumor site over several weeks.

6. Oral Medications for Advanced Cases

In the extremely rare event that a BCC becomes very advanced, invades deep structures, or metastasizes to other parts of the body, oral medications that target the Hedgehog signaling pathway can be used.

Clinically, I also consider non-surgical options like topical therapies, cryotherapy, or photodynamic therapy for superficial or low-risk lesions.

A diagnosis of basal cell carcinoma can be unsettling because it is a form of cancer. However, it is essential to put it in perspective. BCC is the most common and least dangerous type of skin cancer. It is a slow-growing tumor that is extremely unlikely to spread and is almost always completely curable with a variety of highly effective treatments. The most important lesson that a BCC diagnosis teaches us is about the power of prevention. The damage from the sun that causes skin cancer is cumulative over a lifetime. Clinically, I educate patients that while basal cell carcinoma is rarely life-threatening, early detection and sun protection are key to preventing recurrence.

The Skin Cancer Foundation. (n.d.). Basal Cell Carcinoma. Retrieved from https://www.skincancer.org/skin-cancer-information/basal-cell-carcinoma/

The American Academy of Dermatology (AAD). (n.d.). Skin cancer types: Basal cell carcinoma overview. Retrieved from https://www.aad.org/public/diseases/skin-cancer/types/common/bcc

The Mayo Clinic. (2022). Basal cell carcinoma. Retrieved from https://www.mayoclinic.org/diseases-conditions/basal-cell-carcinoma/symptoms-causes/syc-20354187