Basal cell carcinoma is a superficial, slowly growing papule or nodule that derives from certain epidermal cells. Basal cell carcinomas arise from keratinocytes near the basal layer and can be referred to as basaloid keratinocytes. Metastasis is rare, but local growth can be highly destructive. Diagnosis is by biopsy. Treatment depends on the tumor's characteristics and may involve curettage and electrodesiccation, surgical excision, cryosurgery, topical chemotherapy, or, occasionally, radiation therapy or drug therapy.
Basal cell carcinoma is the most common type of skin cancer, with > 2.8 million new cases yearly in the US. It is most common among fair-skinned people with a history of sun exposure and is very rare in darkly pigmented people.
Symptoms and Signs
The clinical manifestations and biologic behavior of basal cell carcinomas are highly variable. They may appear as
Most commonly, the carcinoma begins as a shiny papule, enlarges slowly, and, after a few months or years, shows a shiny, pearly border with prominent engorged vessels (telangiectases) on the surface and a central dell or ulcer. Recurrent crusting or bleeding is not unusual. Commonly, the carcinomas may alternately crust and heal, which may unjustifiably decrease patients' and physicians' concern about the importance of the lesion.
Basal cell carcinomas rarely metastasize but may invade healthy tissues. Rarely, patients die because the carcinoma invades or impinges on underlying vital structures or orifices (eg, eyes, ears, mouth, bone, dura mater).
Treatment should be done by a specialist. The clinical appearance, size, site, and histologic subtype determine choice of treatment—curettage and electrodesiccation, surgical excision, cryosurgery, topical chemotherapy (imiquimod or 5-fluorouracil) and photodynamic therapy, or, occasionally, radiation therapy. Recurrent or incompletely treated cancers, large cancers, cancers at recurrence-prone sites (eg, head and neck), and morphea-like cancers with vague borders are often treated with Mohs microscopically controlled surgery, in which tissue borders are progressively excised until specimens are tumor-free (as determined by microscopic examination during surgery). If patients have metastatic or locally advanced disease and are not candidates for surgery or radiation therapy (eg, because lesions are large, recurrent, or metastatic), vismodegib is now available. Vismodegib inhibits the hedgehog pathway (a pathway that is mutated in most patients with basal cell carcinoma).
Almost 25% of patients with a history of basal cell carcinoma develop a new basal cell cancer within 5 yr of the original carcinoma. Consequently, patients with a history of basal cell carcinoma should be seen annually for a skin examination.
Last full review/revision May 2013 by Gregory L. Wells, MD
Content last modified November 2013