[2] It often appears as a painless raised area of skin, which may be shiny with small blood vessels running over it.

[1] Basal-cell cancer grows slowly and can damage the tissue around it, but it is unlikely to spread to distant areas or results in death.

[2] Basal-cell carcinoma is named after the basal cells that form the lowest layer of the epidermis.

It is thought to develop from the folliculo–sebaceous–apocrine germinative cells called trichoblasts (of note, trichoblastic carcinoma is a term sometimes used to refer to a rare type of aggressive skin cancer that may resemble a benign trichoblastoma, and can also closely resemble basal cell carcinoma).

Individuals with basal-cell carcinoma typically present with a shiny, pearly skin nodule.

It is often difficult to visually distinguish basal-cell cancer from acne scar, actinic elastosis, and recent cryodestruction inflammation.

[20][needs update] Overexposure to the sun leads to the formation of thymine dimers, a form of DNA damage.

Studies of the role of DNA repair in susceptibility to sunlight-induced basal cell carcinoma indicated that reduced DNA repair capacity is one of the underlying molecular mechanisms for sunlight-induced skin carcinogenesis in the general population.

[23] In a small proportion of cases, basal-cell carcinoma also develops as a result of basal-cell nevus syndrome, or Gorlin Syndrome, which is also characterized by keratocystic odontogenic tumors of the jaw, palmar or plantar (sole of the foot) pits, calcification of the falx cerebri (in the center line of the brain) and rib abnormalities.

The cause of this syndrome is a mutation in the PTCH1 tumor suppressor gene located in chromosome 9q22.3, which inhibits the hedgehog signaling pathway.

[29] Adenoidal BCC can be classified as a variant of NBCC, characterized by basaloid cells with a reticulated configuration extending into the dermis.

However, a Cochrane review examining the effect of solar protection (sunscreen only) in preventing the development of basal-cell carcinoma or cutaneous squamous cell carcinoma found that there was insufficient evidence to demonstrate whether sunscreen was effective for the prevention of either of these keratinocyte-derived cancers.

[38] The review did ultimately state that the certainty of these results was low, so future evidence could very well alter this conclusion.

[40] A disadvantage with standard surgical excision is a reported higher recurrence rate of basal-cell cancers of the face,[41] especially around the eyelids,[42] nose, and facial structures.

[44] For basal cell carcinoma excisions on the lower lip, the wound can be covered with a keystone flap.

It is a form of pathology processing called CCPDMA, which means that the entire surgical margin (both edges and deep) is examined.

When accurately utilized with a temperature probe and cryotherapy instruments, it can result in a very good cure rate.

Disadvantages include lack of margin control, tissue necrosis, over or under-treatment of the tumor, and long recovery time.

[55] Chemotherapy often follows Mohs surgery to eliminate the residual superficial basal-cell carcinoma after the invasive portion is removed.

Removing the residual superficial tumor with surgery alone can result in large and difficult-to-repair surgical defects.

One often waits a month or more after surgery before starting the immunotherapy or chemotherapy to make sure the surgical wound has adequately healed.

[53] Vismodegib and sonidegib are drugs approved for specially treating BCC, but are expensive and cannot be used in pregnant women.

Itraconazole, traditionally an anti-fungal medication, has also garnered recent attention for its potential use in the treatment of BCC, especially those that cannot be removed surgically.

Possessing anti-Hedgehog pathway activity, there is clinical evidence that itraconazole has some efficacy either alone or when combined with vismodegib/sonidegib for primary and recurrent BCC.

[57] Research suggests that treatment using Euphorbia peplus, a common garden weed, may be effective.

Radiotherapy can also be useful if surgical excision has been done incompletely or if the pathology report following surgery suggests a high risk of recurrence, for example, if nerve involvement has been demonstrated.

It is used in accordance with the general indications for brachytherapy and especially complex localisations or structures (e.g. earlobe) as well as the genitals.

[53] Photodynamic therapy (PDT) is a new modality for the treatment of basal-cell carcinoma, which is administered by application of photosensitizers to the target area.

However, when recurrence occurs among surgically treated basal-cell carcinomas of the face, there is a strong correlation with tumor thickness.

It is much more common in fair-skinned individuals with a family history of basal-cell cancer and increases in incidence closer to the equator or at higher altitudes.