Basal Cell Carcinoma (BCC) : Causes, Symptoms & Treatment
Definition
- Basal cell carcinoma (basalioma or basal cell cancer) is a cancer that grows on parts of your skin that get a lot of sun.
- Basal cell carcinoma is a common slow-growing cancer that rarely metastasizes.
- It tends to occur at sites subject to chronic sun exposure and in lightly pigmented individuals.
Causes
- Ultraviolet (UV) rays from the sun or from a tanning bed are the main cause of basal cell carcinoma.
Epidemeology
- It is estimated that in excess of 1 million basal cell carcinomas are treated in the United States annually.
- By far the most important risk factor is sun exposure; basal cell carcinoma is more common in warm southern regions of the United States, and its incidence is 40-fold higher in sunny climates near the equator, such as Australia, than it is in Northern European locales.
- Individual tumors usually are cured by local excision, but approximately 40% of patients will develop another basal cell carcinoma within 5 years.
- Advanced lesions may ulcerate, and extensive local invasion of bone or facial sinuses may occur if the lesions are neglected for many years.
Pathogenesis
- Basal cell carcinoma is associated with dysregulation of the Hedgehog pathway. Inherited defects in the PTCH
gene, a tumor suppressor that regulates Hedgehog pathway signaling, cause familial basal cell carcinomas in Gorlin syndrome. - The Hedgehog pathway is an important regulator of embryonic development, and subtle developmental anomalies are also often noted in affected persons. Some component of the hedgehog pathway is mutated in the great majority of sporadic basal cell carcinomas as well. Mutations in TP53 are also common in both familial and sporadic tumors.
Morphology
Grossly,
- Basal cell carcinomas manifest as pearly papules, often with prominent, dilated subepidermal blood vessels (telangiectasia).
- Some tumors contain melanin pigment and thus appear similar to melanocytic nevi or melanomas.
Microscopically,
- The tumor cells resemble the normal epidermal basal cell layer from which they are derived. Because they may arise from either the epidermis or the follicular epithelium, they are not encountered on mucosal surfaces.
- Two common patterns are seen: multifocal growths originating from the epidermis (superficial pattern), or nodular lesions growing downward into the dermis as cords and islands of variably basophilic cells with hyperchromatic nuclei, embedded in a fibrotic or mucinous stromal matrix.
- Peripheral tumor cell nuclei align in the outermost layer (a pattern termed palisading), which often separates from the stroma, creating a characteristic cleft.
Clinical Symptoms
- Individuals with a basal-cell carcinoma typically present with a shiny, pearly skin nodule.
- You may notice a skin growth in a dome shape that has blood vessels in it. It can be pink, brown, or black.
Treatment
The goal is to get rid of the cancer while leaving as small a scar as possible.
To choose the best treatment, your doctor will consider the size and place of the cancer, and how long you’ve had it.
Prevention
- Inspect your skin for new growths.
- Avoid too much sun.
- Use sunscreen of good SPF.
- Dress right. Wear a broad-brimmed hat and cover up as much as possible, such as long-sleeved shirts and long pants.
