A 54-year-old man presents with a finger laceration, but you notice a lip lesion that he says has been growing larger over the past six months. He says it occassionally bleeds when unprovoked. He has a 20-year cigarette smoking history. What are you concerned about?
Diagnosis: Squamous Cell Carcinoma
Squamous cell carcinoma represent more than 90 percent of all head and neck cancers, four percent of all malignancies in the United States, and is the most common malignancy of the oral cavity. (Rev Stomatol Chir Maxillofac 2009;110:278.) It is the second most common skin cancer (with basal cell being first) in the country, and results from malignant proliferation of epidermal keratinocytes. A damaged p53 tumor suppressor gene has been identified in approximately 50 percent of cases. (Proc Natl Acad Sci U S A 1991;88:10124.)
The primary risk factors for squamous cell carcinoma of the mouth are alcohol and tobacco, smoked and smokeless. Exposure to betel quid is also a known carcinogen in developing countries. Other risk factors are ionizing radiation, dental disease, chronically inflamed tissue (e.g., chronic skin ulceration), exposure to the sun (cumulative), tanning beds, the Epstein-Barr virus, human papillomavirus infection, and arsenic (ingestion and topical). Immunodeficiency, including HIV and pharmacologic suppression, is also a recognized risk factor for developing squamous cell carcinoma. Interestingly, as many as 35 percent of heart transplant patients will develop a skin cancer within 10 years post-transplant. (Arch Dermatol 2009;145:1391.) Some people also have a genetic predisposition to developing cutaneous squamous cell carcinoma and a personal history of a variety of skin conditions including albinism, xeroderma pigmentosum, and epidermolysis bullosa.
Actinic keratosis is a known precursor for cutaneous squamous cell carcinoma (Cutis 2007;79[4 Suppl]:18), but the conversion rate to a malignant lesion appears to be less than five percent. (Cancer 2009;115:2523.) Large prospective studies have yet to be performed, however. (Cutis 2011;87:201.) Incidence is higher in regions near the equator and in light-skinned individuals, and occurs nearly twice as often in men than women. It also most commonly occurs in individuals in their 50s and 60s.
Symptoms at clinical presentation can include tender, painful, nonhealing lesions or sores and hypertrophic white or red skin. Lesions most commonly occur on the lip, floor or roof of the mouth, tongue, soft palate, and gums, but can occur on other areas of the oral cavity. Large lesions can result in loose teeth and painful chewing or swallowing. Large lesions metastasize to regional lymphatic drainage sites, so patients may have signs of lymphadenopathy.
Treatment depends on the stage of the tumor — its depth or extent of tissue invasion and regional lymph node involvement. CT scanning is now routinely used to determine if bony (mandibular) involvement exists, but MRI demonstrates better tissue visualization. PET scanning may be necessary for determining metastatic adenopathy if CT and MRI are equivocal. Surgery is the treatment of choice for lower lip lesions. (J Oral Maxillofac Surg 2008;66:1259.) Squamous cell carcinoma lesions that are more than 2 cm in diameter, more than 4 mm thick, moderately or poorly differentiated, located on the ear, lip, hand, feet, or genitals, have lymphatic extension, are recurrent, arose from scars or chronic skin disease, or occur in immunosuppressed patients are considered high risk. (Expert Rev Anticancer Ther 2011;11:763.)
Five-year survival rates for squamous cell carcinoma of the head and neck are approximately 60 percent when untreated. Rates can be as high as 80 percent for small or nondisseminated lesions, however. Lesions on the lip, because of the rich vascular supply, have a fairly high rate of metastasis (nearly 14%) compared with other sites on the head and neck. (J Am Acad Dermatol 1992;26:976.) Lesions of the upper lip are more aggressive and metastasize earlier than those on the lower lip. Local extension into the nasal cavity and maxilla make treatment with good functional and cosmetic outcomes more challenging.
Prevention of squamous cell carcinoma includes sun protection. This patient was referred to dermatology for an urgent follow-up where a skin biopsy confirmed squamous cell carcinoma. The patient was then lost to follow-up.
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