However, superficial basal-cell cancer can present as a red patch similar to eczema. Infiltrative or morpheaform basal-cell cancers can present as a skin thickening or scar tissue – making diagnosis difficult without using tactile sensation and a skin biopsy. It is often difficult to visually distinguish basal-cell cancer from acne scar, actinic elastosis, and recent cryodestruction inflammation. Cause
The majority of basal-cell carcinomas occur on sun-exposed areas of the body. Pathophysiology
Basal-cell carcinoma is named after the basal cells that populate the lowest layer of the epidermis due to the histological appearance of the cancer cells under the microscope. Nevertheless, not all basal-cell carcinomas actually originate within the basal layer. Basal-cell carcinomas are thought to develop from the folliculo–sebaceous–apocrine germinative cells known as trichoblasts. Trichoblastic carcinoma is a term used to describe a rare and potentially aggressive malignancy that is also thought to arise from trichoblasts and may resemble a benign trichoblastoma (differential diagnosis can be challenging). It has been suggested that lesions diagnosed as trichoblastic carcinoma may actually themselves be basal-cell carcinoma.Overexposure to sun leads to the formation of thymine dimers, a form of DNA damage. While DNA repair removes most UV-induced damage, not all crosslinks are excised. There is, therefore, cumulative DNA damage leading to mutations. Apart from the mutagenesis, overexposure to sunlight depresses the local immune system, possibly decreasing immune surveillance for new tumor cells. Basal-cell carcinomas can often come in association with other lesions of the skin, such as actinic keratosis, seborrheic keratosis, squamous cell carcinoma.
Basal-cell carcinoma (BCC), also known as basal-cell cancer, is the most common type of skin cancer. It often appears as a painless raised area of skin, which may be shiny with small blood vessels running over it. It may also present as a raised area with ulceration. Basal-cell cancer grows slowly and can damage the tissue around it, but it is unlikely to spread to distant areas or result in death.Risk factors include exposure to ultraviolet light, having lighter skin, radiation therapy, long-term exposure to arsenic and poor immune-system function. Exposure to UV light during childhood is particularly harmful. Tanning beds have become another common source of ultraviolet radiation. Diagnosis often depends on skin examination, confirmed by tissue biopsy.It remains unclear whether sunscreen affects the risk of basal-cell cancer. Treatment is typically by surgical removal. This can be by simple excision if the cancer is small; otherwise, Mohs surgery is generally recommended. Other options include electrodesiccation and curettage, cryosurgery, topical chemotherapy, photodynamic therapy, laser surgery or the use of imiquimod, a topical immune-activating medication. In the rare cases in which distant spread has occurred, chemotherapy or targeted therapy may be used.Basal-cell cancer accounts for at least 32% of all cancers globally. Of skin cancers other than melanoma, about 80% are basal-cell cancers. In the United States, about 35% of white males and 25% of white females are affected by BCC at some point in their lives. Signs and symptoms
Individuals with a basal-cell carcinoma typically present with a shiny, pearly skin nodule.