Home > Medical Reference > Patient Education

Ask the Expert

Get answers to your Melanoma questions.

Note: This is for informational purposes only. Doctors cannot provide a diagnosis or individual treatment advice via e-mail. Please consult your physician about your specific health care concerns.

Melanoma and other skin cancers - Introduction

Description

An in-depth report on the causes, diagnosis, treatment, and prevention of melanoma and nonmelanoma skin cancers.

Alternative Names

Skin cancer; Squamous cell cancer; Basal cell cancer; Actinic keratosis; Nonmelanoma skin cancer

Introduction:

Skin cancer is cancer that starts in the skin. Skin cancers are divided into two major groups:

Nonmelanoma, which includes basal cell cancer and squamous cell cancer
Melanoma, the deadliest form of skin cancer

Different skin cancers start in different layers or cells of the skin. To understand how skin cancer develops, it is useful to know something about the skin.

The Skin. The skin is the largest organ in the body and consists of layers.

The outermost layer of the skin is called the epidermis. It is only about 20 cells deep, roughly as thick as a sheet of paper.
The dermis ranges in thickness from 1 - 4 millimeters (about 1/32 - 1/8 inch). The dermis contains tiny blood and lymph vessels, which increase in number deeper in the skin.

The skin is the largest organ of the body. The skin and its components (hair, nails, sweat, and oil glands) make up the integumentary system. One of the main functions of the skin is protection. It protects the body from external factors, such as bacteria, chemicals, and temperature. The skin contains secretions that can kill bacteria, and the pigment melanin provides a chemical defense against ultraviolet light that can damage skin cells. The skin also helps control body temperature.

Melanocytes. A layer of cells between the epidermis and the dermis called melanocytes produces a brown-black skin pigment (melanin) that determines skin and hair color. Melanin also helps protect against the damaging rays of the sun.

As a person ages, melanocytes often spread (proliferate). They form clusters that appear on the skin surface as small, dark, flat, or dome-shaped spots, which are usually harmless moles or liver spots.

When cell proliferation occurs in a controlled and contained manner, the resulting spot is noncancerous (benign) and is commonly referred to as a mole or nevus.
Sometimes, however, pigment cells grow out of control and become a cancerous and life-threatening melanoma.

Click the icon to see an image of melanin.

Resources

www.aad.org -- American Academy of Dermatology
www.cancer.org -- American Cancer Society
www.asds.net -- American Society for Dermatologic Surgery
www.mpip.org -- Melanoma Patients' Information Page
www.cancer.gov -- National Cancer Institute
www.nccn.org -- National Comprehensive Cancer Network
www.skincancer.org -- The Skin Cancer Foundation
www.epa.gov/sunwise/uvindex.html -- UV index information

References

Abbasi NR, Yancovitz M, Gutkowicz-Krusin D, Panageas K, Googe P, King R, et al. Utility of lesion diameter in the clinical diagnosis of cutaneous melanoma. Arch Dermatol. 2008;144:469-474.

American Cancer Society. Cancer Facts and Figures 2008. Atlanta, GA: American Cancer Society; 2008.

Anderson L, Schmieder GJ, Werschler WP, et al. Randomized, double-blind, double-dummy, vehicle-controlled study of ingenol mebutate gel 0.025% and 0.05% for actinic keratosis. J Am Acad Dermatol. 2009;60(6):934-43.

Basal cell and squamous cell cancers: NCCN Medical Practice Guidelines and Oncology;V.1.2009. Accessed July 15, 2009.

Braathen LR, Szeimies RM, Basset-Seguin N, Bissonnette R, Foley P, Pariser D, et al. Guidelines on the use of photodynamic therapy for nonmelanoma skin cancer: an international consensus. International Society for Photodynamic Therapy In Dermatology, 2005. J Am Acad Dermatol. 2005;56:125-143.

Brantsch KD, Meisner C, Schonfisch B, Trilling B, Wehner-Caroli J, Rocken M, et al. Analysis of risk factors determining prognosis of cutaneous squamous-cell carcinoma: a prospective study. The Lancet Oncology. 2008;9:713-720.

Clinical practice guideline for melanoma: NCCN Medical Practice Guidelines and Oncology;V.2.2009. Accessed July 15, 2009.

Cyr PR. Atypical Moles. Am Fam Physician. 2008;78(6):735-40. Review.

deBerker D, McGregor JM, Hughes BR. Guidelines for the management of actinic keratoses. Br J Dermatol. 2007;156:222-230.

Eggermont AM, Suciu S, Santinami M, et al: EORTC Melanoma Group. Adjuvant therapy with pegylated interferon alfa-2b versus observation alone in resected stage III melanoma: final result of EORTC 18991, a randomised phase III trial. Lancet. 2008;372(9633):117-26.

Garcia C, Polette E, Crowson AN. Basosquamous carcinoma. J Am Dermatol. 2009;60(1):137-43.

Goodson AG, Grossman D. Strategies for early melanoma detection: Approaches to the patient with nevi. J Am Acad Dermatol. 2009;60(5):719-35: quiz 736-8. Review.

Guadagnolo BA, Zagars GK. Adjuvant radiation therapy for high-risk notal metastases from cutaneous melanoma. Lancet Oncol. 2009;10(4):409-16.

Hexsel, CL, Bangert SD, Hebert AA, et al. Current sunscreen issues: 2007 Food and Drug Administration sunscreen labelling recommendations and combination sunscreen/insect repellent products. J Am Dermatol. 2008;59(2):316-23. Review.

Lachiewicz AM, Berwick M, Wiggins CL, Thomas NE. Survival differences between patients with scalp or neck melanoma and those with melanoma of other sites in the surveillance, epidemiology, and end results (SEER) program. Arch Dermatol. 2008;144:515-521.

Lange JR, Fecher LA, Sharfman WH, et al. Melanoma. In: Abeloff MD, Armitage JO, Nierderhuber JE, Kastan MB, McKenna WG, eds. Abeloff's Clinical Oncology. 4th ed. Philadelphia, Pa: Churchill Livingstone; 2008:chap 73.

Lautenschlager S, Wulf HC, Pittelkow MR. Photoprotection. The Lancet [early online publication]. May 3, 2007.

Markovick SN, Erickson LA, Rao RD, Weenig RH, Pockaj BA, Bardia A, et al. Malignant melanoma in the 21st century, part 1:epidemiology, risk factors, screening, prevention, and diagnosis. Mayo Clin Proc. 2007;82:364-380.

Markovick SN, Erickson LA, Rao RD, Weenig RH, Pockaj BA, Bardia A, et al. Malignant melanoma in the 21st century, part 2: staging, prognosis, and treatment. Mayo Clin Proc. 2007;82:490-513.

Morton CA, mckenna KE, Rhodes LE:British Association of Dermatologists Therapy Guidelines and Audit Subcomittee and the British Photodermatology group. Guidelines for topical photodynamic therapy: update. Br J Dermatol. 2008;159(6):1245-66. Review.

Morton DL, Thompson JF, Cochran AJ Mozzillo N, Elashoff R, Essner R, et al. Sentinel-node biopsy or nodal observation in melanoma. N Engl J Med. 2006;355:1307-1317.

Olsen CM, Zens MS, Stukel TA, et al. Nevus density and melanoma risk in women: to test the divergent pathway hypothesis. Int J Cancer. 2009;124(4):937-44.

Ridky TW. Nonmelanoma skin cancer. J Am Acad Dermatol. 2007;57:484-501.

Savel MS, Wong SI. Review of evidence-based support for pretreatment imaging in melanoma. J Natl compr Canc netw. 2009;7(3):281-9. Review.

Suh KY, Bolognia JL. Signature nevi. J Am Acad Dermatol. 2009;60(3):508-14. Review.

Telfer NR, Colver GB, Morton CA. Guidelines for the Management of Basal Cell Carcinoma. BJD. 2008;159:35-48.

Tran KT, Wright NA, Cockerell CJ. Biopsy of the pigmented lesion-when and how. J Am Acad Dermatol. 2008;59(5):852-71. Review.

Treatment for Metastatic Ocular Melanoma. NCI Cancer Bulletin. March 7, 2006;3(10):8.

Vestergaard ME, Macaskill P, Holt PE, et al. Dermoscopy compared with naket eye examination for the diagnosis of primary melanoma: a meta-analysis of studies performed in a clinical setting. Br J Dermatol. 2008;159(3):669-76.

Warycha MA, Zakrzewski J, Ni Q, et al. Meta-analysis of sentinal lymph node positivity in thin melanoma. Cancer. 2009;115(4):869-79.

Wood GS, Gunkel J, Stewart D, et al. Nonmelanoma skin cancers: basal and squamous cell carcinomas. In: Abeloff MD, Armitage JO, Nierderhuber JE, Kastan MB, McKenna WG, eds. Abeloff's Clinical Oncology. 4th ed. Philadelphia, Pa: Churchill Livingstone; 2008:chap 74.

Zeichner JA, Stern DW, Uliasz A, et al. Placebo-controlled double-blind randomized pilot study of imiquimod 5% cream applied once per week for 6 months for the treatment of actinic keratoses. J Am Acad Dermatol. 2009;60(1):59-62.

Reviewed last on: 7/30/2009
Harvey Simon, MD, Associate Professor of Medicine, Harvard Medical School; Physician, Massachusetts General Hospital. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.

The information provided herein should not be used during any medical emergency or for the diagnosis or treatment of any medical condition. A licensed medical professional should be consulted for diagnosis and treatment of any and all medical conditions. Call 911 for all medical emergencies. Links to other sites are provided for information only -- they do not constitute endorsements of those other sites. © 1997- A.D.A.M., Inc. Any duplication or distribution of the information contained herein is strictly prohibited.

A.D.A.M., Inc. is accredited by URAC, also known as the American Accreditation HealthCare Commission (www.urac.org). URAC's accreditation program is an independent audit to verify that A.D.A.M. follows rigorous standards of quality and accountability. A.D.A.M. is among the first to achieve this important distinction for online health information and services. Learn more about A.D.A.M.'s editorial policy, editorial process and privacy policy. A.D.A.M. is also a founding member of Hi-Ethics and subscribes to the principles of the Health on the Net Foundation (www.hon.ch).

Connect with UMMC

© 2011 University of Maryland Medical Center (UMMC). All rights reserved.
UMMC is a member of the University of Maryland Medical System,
22 S. Greene Street, Baltimore, MD 21201. TDD: 1-800-735-2258 or 1.866.408.6885