Porth's Essentials of Pathophysiology, 4e

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Integumentary Function

U N I T 1 3

Squamous Cell Carcinoma Squamous cell carcinomas are the second most common malignant tumors arising on sun-exposed sites in older people, exceeded only by basal cell carcinoma. In addi- tion to sun exposure, occupational exposure to arsenic (i.e., Bowen disease), industrial tars, coal, and paraffin increase the risk for squamous cell carcinoma. Men are twice as likely as women to have squamous cell carci- noma. Black persons are rarely affected. Squamous cell cancers are composed of tumor cells that resemble the epidermal cells of the stratum spino- sum to varying degrees and extend into the adjacent dermis. 68 There are two types of squamous cell carci- nomas: intraepidermal (termed in situ carcinoma) and invasive carcinoma. Intraepidermal squamous cell carci- noma remains confined to the epidermis for a long time. However, at some unpredictable time, it penetrates the basement membrane to the dermis and metastasizes to the regional lymph nodes. It then converts to invasive squamous cell carcinoma . The invasive type of squa- mous cell carcinoma can develop from intraepidermal carcinoma or from a premalignant lesion (e.g., actinic keratoses). It may be slow growing or fast growing with metastasis. Squamous cell carcinoma is a red, scaling, keratotic, slightly elevated lesion with an irregular border, usually with a shallow chronic ulcer (Fig. 46-24). The lesions usually lack the pearly rolled border and superficial

There are two types of basal cell carcinoma, deter- mined by their pattern of growth: superficial basal cell carcinomas originating from the epidermis and extending upward, and nodular basal cell carcinomas in which the tumor grows downward into the dermis. Nodular basal cell carcinoma, the classic type, pres- ents as a small, flesh-colored or pink, smooth, trans- lucent nodule that enlarges over time (Fig. 46-23). Telangiectatic vessels frequently are seen beneath the surface. Over the years, there is a central depression that forms and develops into an ulcer surrounded by the original shiny, waxy border. Superficial basal cell carcinoma presents as a scaly erythematous patch or plaque. Both nodular and superficial forms may con- tain melanin, imparting a brown, blue, or black color to the lesions. Since basal cell carcinoma is highly curable if detected and treated early, all suspected lesions should undergo biopsy for diagnosis. The treatment depends on the site and extent of the lesion. The most impor- tant treatment goal is complete elimination of the lesion. Also important is the maintenance of function and optimal cosmetic effect. Curettage with electro- desiccation, surgical excision, irradiation, laser, cryo- surgery, and chemosurgery are effective in removing all cancerous cells. Immune therapy, gene therapy, and photodynamic therapy are emerging treatments. Persons should be checked at regular intervals for recurrences.

FIGURE 46-24. Squamous cell carcinoma as manifested by a raised lesion of the skin of the face. (From National Cancer Institute Visuals. No. AV-CDR728323. Courtesy of Kelly Nelson, photographer.)

FIGURE 46-23. Nodular basal cell carcinoma, which presents as a reddish-brown papule, often with telangiectatic blood vessels, and a central depression with rolled borders. (From National Cancer Institute Visuals. No. AV-8500-3608.)