About basal cell carcinoma

Basal cell carcinoma (BCC) is a cancer arising from the basal cell layer of the epidermis. It is the most commonly occurring human cancer. Despite only rarely metastasizing, these aggressive tumors can cause profound local tissue destruction. The majority of basal cell carcinomas are caused by exposure to ultraviolet radiation in the form of sunlight. It occurs most frequently in fair-skinned, light-eyed individuals with other evidence of sun-damage to their skin.

There are four main clinical subtypes of BCC: nodular, pigmented, superficial, and sclerotic. The nodular type is most common, appearing as the classic “pearly papule” with a central depression, associated telangiectasia (small blood vessels), and a rolled, waxy border. It is often found on the face, especially the nose. The pigmented type, as the name suggests, is a blue or black nodule, papule, or plaque, often speckled, with a rolled border. Superficial BCC appears similar to eczema, and is often found on the trunk. It is red, scaly, well-demarcated, and has a pearly border. The scarring type appears as a white atrophic plaque that can be confused with a scar. It is the most aggressive and, fortunately, least common, subtype of BCC. Another type is the Pinkus type, also known as fibroepithelioma. It is distinguished by its unique reticulated appearance on histology. The Pinkus type of BCC is most frequently found in the lumbrosacral area.

With what can basal cell carcinoma be confused?

Nodular BCC can resemble squamous cell carcinoma, non-pigmented nevus, molluscum contagiosum, and sebaceous hyperplasia. Pigmented BCC can be confused with other pigmented lesions such as pigmented nevus and, importantly,malignant melanoma. Seborrheic keratosis is also in the differential. Superficial BCC can be confused with eczema,dermatitis, psoriasis, and Bowen’s disease. Scarring BCC, as the name suggests, can be confused with a scar or sometimes a squamous cell carcinoma.

How is basal cell carcinoma diagnosed?

A BCC might be suspected after a routine skin exam. A new growth that does not heal and bleeds easily is suspicious for BCC, especially in fair skinned persons with a history of sun exposure and evidence of actinic (sun) damage. This suspicion will be confirmed with a skin biopsy, either punch or shave, which is interpreted by a dermatopathologist. As the cancer’s name suggests, its cells resemble the basal cells of the epidermis. The tumor extends from the epidermis into the dermis with various morphologies such as nodules, cysts, buds, and strands. The use of a specialized instrument called a dermatoscope might assist your dermatologist in determining if a biopsy is required. Obtaining a skin biopsy is the standard of care in diagnosing basal cell carcinoma.

How is basal cell carcinoma treated?

Possibilities include scalpel excision, curettage and electrodessication, cryotherapy, radiation therapy,  topical chemotherapeutic agents. The two most common treatments are surgical excision with suture closure and electrodessication and curretage. For high-risk basal cell carcinomas, Mohs micrographic surgery may provide the lowest risk of recurrence.

The topical chemotherapeutic agents imiquimod and 5-fluorouracil are sometimes uses, especially for superficial basal cell carcinomas.

Radiotherapy is sometimes appropriate for basal cell carcinoma.

For metastatic and unresectable tumors, a class of oral medications called hedgehog pathway inhibitors can be used.

The choice of treatment depends on various parameters such as size, location, whether it is a recurrence, histopathologic type, and age and general health of the patient.

What is Mohs surgery for basal cell carcinoma?

A special form of surgery, Mohs’ micrographic surgery, is sometimes performed for basal cell carcinoma and other skin cancers. In this procedure, the surgeon examines the excised tissue in real time to ensure that it is free of cancerous cells. It enables the surgeon to remove only as much tissue as is necessary to ensure tumor-free margins.

What is a high-risk basal cell carcinoma?

Most basal cell carcinomas are low-risk, but some features make a basal cell carcinoma high-risk. These include:

  • Located in area H of the face.
  • Large size
  • Poorly defined borders
  • Recurrent tumor
  • Immunosuppressed patients
  • Site of previous radiation
  • High-risk histopathological subtype (presence of perineural invasion, micronodular, infiltrative, morpheaform)

What is the prognosis for basal cell carcinoma?

These tumors rarely metastasize (spread to a remote location), with an estimated rate of 0.003%. However, they can be aggressive locally. If not treated in a timely fashion, a BCC can result in significant deformity. Annual follow-up is recommended; up to 35% of patients will develop a second BCC within five years.

How is basal cell carcinoma prevented?

Avoidance of further sun damage is critical. This includes the daily use of sunscreens with a minimum SPF of 30, protective clothing such as a wide-brimmed hat and long sleeved shirt, and sun avoidance, especially midday when the sun is strongest.

More about basal cell carcinoma

Image links

DermNetNZ: Fact Sheet and Photos of Basal Cell Carcinoma

Other useful links

The Skin Cancer Foundation: Basal Cell Carcinoma
Basal Cell Carcinoma. e-medicine.