Basal cell carcinoma (BCC)

Basal cell carcinoma appears predominantly on regions of the skin already exposed to UV rays, in individuals who have light skin thus being prone to sunburn. The migration of these individuals, especially in childhood, to sunny countries, is associated with an increase in the rate of skin cancers. Although basal cell carcinoma occurs in adults, the tumor may develop in children as well. Nodular basal cell carcinoma occurs at an older age than superficial basal cell carcinoma and is more common around the head, as opposed to the trunk, which is more common in superficial tumors.

Basal cell carcinoma is most commonly seen in individuals with light skin that live in low altitude countries. The record for this type of carcinoma was recorded in Queensland, Australia, where the incidence is 2000 per 100,000 individuals. The rate of basal cell carcinomas has increased in elderly individuals.

BCC is a malignancy that arises from epidermal basal cells. There are several clinical types of BCC:

• Rodent ulcer BCC, which begins as a small node, as a pearl, sometimes with small telangiectatic vessels on its surface.
• Pigmented BCC when large quantities of melanin may be present in the tumor. Although clinically not more aggressive than the rodent ulcer variant, pigmented BCC may be misinterpreted as malignant melanoma.
• Superficial BCC consists of one or more erythematous, crusty plates, which increase slowly. Although it is more common on the trunk and extremities, the head and neck may also be affected. The lesions can be confused with benign inflammatory dermatoses, especially with eczema and psoriasis.
• Morpheaform BCC (fibrous) manifest as a solitary, smooth or slightly depressible, indurated, whitish or yellowish plaque. It usually has hard to determine edges, a feature associated with high potential for rapid subclinical extension.

Basal cell carcinomas are local invasive tumors and metastases occur in less than 1 / 10,000 tumors. Morbidity increases for deep invasion tumors, which can extend to underlying tissues such as bone tissue, resulting in fusion between planes, especially in the face, where the tumor could penetrate through the bone channels made by the nerves. Morbidity also increases in the case of neglected tumors, which can measure more than 10 cm in diameter, and which have been described as giant cell carcinomas.

Multiple recurrences with deep residual tumors on the head may be associated with high morbidity, as basal cell carcinomas may eventually penetrate the skull. Increased recurrence is associated with infiltrating, morpheaform and micronodular basal cell carcinoma, because surgical safety margins may be underestimated.

The possibility of existence of the nevoid basal cell carcinoma syndrome could be considered in children with basal cell carcinomas. Families may be screened for the PTCH1 gene mutation. Low expression of bcl-2 protein has been shown to correlate with more aggressive basal cell carcinomas with infiltrating or morphing pattern compared with superficial and nodular ones.

Recurrence of basal cell carcinomas is more common in lesions of the nose and the nasolabial fold, but this may be due to the difficulty in achieving adequate safety margins.

Recurrent tumors after radiotherapy are usually aggressive and infiltrative. The lesions with metastases are usually enlarged, ulcerated, with deep and recurrent infiltration. The risk of developing another basal cell carcinoma is increased in men, 60-year-old and up, mostly in the trunk area.

The evolution of skin carcinomas

Basal cell carcinomas are local invasive tumors and metastases occur in less than 1 / 10,000 tumors. Morbidity increases for deep invasion tumors, which can extend to underlying tissues such as bone tissue, resulting in fusion between planes, especially in the face, where the tumor could penetrate through the bone channels made by the nerves. Morbidity also increases in the case of neglected tumors, which can measure more than 10 cm in diameter, and which have been described as giant cell carcinomas.

Multiple recurrences with deep residual tumors on the head may be associated with high morbidity, as basal cell carcinomas may eventually penetrate the skull. Increased recurrence is associated with infiltrating, morpheaform and micronodular basal cell carcinoma, because surgical safety margins may be underestimated.

The possibility of existence of the nevoid basal cell carcinoma syndrome could be considered in children with basal cell carcinomas. Families may be screened for the PTCH1 gene mutation. Low expression of bcl-2 protein has been shown to correlate with more aggressive basal cell carcinomas with infiltrating or morphing pattern compared with superficial and nodular ones.

Recurrence of basal cell carcinomas is more common in lesions of the nose and the nasolabial fold, but this may be due to the difficulty in achieving adequate safety margins.

Recurrent tumors after radiotherapy are usually aggressive and infiltrative. The lesions with metastases are usually enlarged, ulcerated, with deep and recurrent infiltration. The risk of developing another basal cell carcinoma is increased in men, 60-year-old and up, mostly in the trunk area.