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Basal Cell Carcinoma

Basal cell carcinomas are among the most common cutaneous malignant
tumors. Two thirds of basal cell carcinomas are associated with actinic damage; however,
one third occur in areas not exposed to the sun. These lesions, although histologically
malignant, only rarely metastasize. However, if neglected, they are destructive and can
cause disability or death by invading adjacent soft tissue, cartilage.

A basal cell carcinoma usually presents as a dome-shaped, white to pink papule or nodule
with a raised pearly border and prominent superficial vessels. There may be scaling, crusting,
or ulceration. Various other clinical types of basal cell carcinoma have also been
observed. The cystic variety is translucent and contains gelatinous fluid. The sclerosing
variety, appearing as a fibrotic, whitish, macular plaque with indistinct borders, may easily be 
overlooked. Superficial multicentric lesions may resemble asymptomatic eczematous plaques,
although close inspection reveals a fine, raised pearly border. The pigmented variety may be
confused clinically with a malignant melanoma. A rodent ulcer is usually a present.

Multiple basal cell carcinomas, ranging in number from a few to hundreds, may occur in
patients with the basal cell nevus syndrome, an autosomal dominant condition. The basal
cell carcinomas begin to appear after puberty on the face, the trunk, and the extremities.
Many are highly invasive and involve the embryonic cleft areas of the face, especially the
regions around the eyes and the nose. Other associated features of the basal cell nevus
syndrome include odontogenic jaw cysts, palmar and plantar pits, ectopic calcification
(particularly of the falx cerebri), and ocular and skeletal abnormalities such as hypertelorism
and shortening of the fourth and fifth metacarpals termed, skin cancer.

Histopathologic examination of basal cell epitheliomas reveals collections of cells with
dark-staining nuclei and scant cytoplasm. The periphery of the cell masses shows cells in a
palisade arrangement resembling the basal layer of the epidermis.

Recurrent basal cell carcinomas are usually difficult to cure, but Mohs’ microscopic
controlled surgery, when it is performed by a specially trained physician, is effective in
eradicating the entire tumor. Routine in vivo chemosurgical fixation of the tumor with zinc
chloride paste is no longer required. In the current procedure, fresh tissue is removed.

Indications for microscopic controlled excision of skin cancer include recurrent basal cell
epitheliomas and squamous cell carcinomas; tumors with indistinct margins, such as
sclerosing basal cell epitheliomas; and lesions in such areas.