04 Malignant Skin Lesions

Screening and diagnosis in one study multivariate

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Unformatted text preview: long-term mild exposure, though the exact mechanism behind the pathogenesis remains unknown. Screening and Diagnosis In one study, multivariate analysis identified the following six risk factors as important in the development of malignant melanoma27: 1. A family history of melanoma; 2. A history of three or more blistering sunburns before the age of 20; 3. Blonde or red hair; 4. The presence of actinic keratosis; 5. A history of 3 or more years of an outdoor summer job as a teenager; and 6. Marked freckling on the upper part of the back. For a person with one or two of these factors, the risk of melanoma is increased 3.5-fold; for a person with three or more, the risk is increased 20-fold. The recommended frequency for melanoma screening should be based on these six risk factors. Routine screening of low-risk patients through total body skin examinations performed by healthcare providers is not a supported practice. Self-screening, however, is clearly recommended, and excellent educational materials on this subject are available from the American Academy of Dermatology and the American Cancer Society. Nevertheless, physicians should take every opportunity to screen patients as the occasion arises; in general, the lesions found by physicians are significantly thinner than those detected by patients or their spouses.28 For effective treatment of melanomas, early recognition is critical. The ABCD (Asymmetry, Border irregularity, Color variegation, Diameter) guidelines for pigmented lesions are frequently used as aids to melanoma identification [see Table 1].29 Melanomas often occur on sun-exposed areas of the upper trunk and the extremities, and they are typically asymmetric, with irregular borders and variegated pigmentation [see Figure 3a]. Occasionally, they lack pigmentation or are associated with significant gross ulceration. Any lesion that appears suspicious for melanoma should undergo biopsy. Histologically, melanomas are characterized by atypical melanocytes with mitotic figures. Special staining, most commonly with HMB-45 or S100, may also be performed. Histologic Subtypes Melanoma may be classified into histologic subtypes on the basis of growth pattern and anatomic location. It should be kept in mind, b a Figure 3 Shown are (a) a typical melanoma and (b) an acral lentiginous melanoma. © 2006 WebMD, Inc. All rights reserved. ACS Surgery: Principles and Practice 3 BREAST, SKIN, AND SOFT TISSUE 4 Malignant Skin Lesions — 5 Table 2—Clark System for Staging Melanoma Clark Level Level I Degree of Tumor Invasion 5-Year Survival (%) Malignant melanocytes are confined to epidermis 99 Level II Malignant melanocytes infiltrate papillary dermis singly or in small nests 95 Level III Malignant melanocytes fill and expand papillary dermis, with extension of tumor to papillary-reticular dermal interface (usually signifying vertical growth phase) 82 Level IV Malignant melanocytes infiltrate reticular dermis in significant fashion 71 Level V Malignant melanocytes infiltrate subcutaneous fat 49 however, that the spe...
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This note was uploaded on 03/21/2011 for the course ONC 01 taught by Professor Dzodic during the Spring '11 term at Multimedia University, Cyberjaya.

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