Signs and Symptoms of Melanoma

In most cases, melanoma initially appears as a flat or slightly raised growth that displays a variety of colors (e.g., black and brown, or gray, pink, blue, and white). Its edges are poorly outlined and may blur into the surrounding skin and its shape is often asymmetrical (i.e., if one could fold it in half, the edges would not meet). The growth may not exhibit any symptoms, or it may bleed, itch, ooze, or feel sore. Common sites include the trunk (especially the upper back), the lower legs, the head, and the neck.

Melanoma typically originates in the upper layer of the skin, but it can rapidly penetrate into deeper layers and then spread through the bloodstream or lymphatic system to distant sites in the body. Common areas of metastasis include the lungs, liver, brain, and bone.

To distinguish a normal mole from a melanoma, dermatologists have developed the ABCD rule. According to this guide, the following features characterize melanoma:

  • Asymmetrical lesions: the different halves of the mole do not look like each other.
  • Border irregularity: the edges of the mole are indented or notched.
  • Color variation: the mole is not the same color all over.
  • Diameter greater than the size of a pencil eraser tip is suspect.

Not all melanomas display the features defined by the ABCD rule, so it is necessary to monitor unusual skin symptoms that last longer than 2 weeks.

Standard warning signs of melanoma include a change in mole color from black or brown to white, red, or blue, and development of a new raised, or papular (a solid, elevated lesion) mole. Any new, colored growths or changes in existing moles or lesions should be reported to a dermatologist as soon as possible. Skin cancer rarely is painful, so even lesions that do not hurt demand immediate attention. The sooner the mole is examined, the better the prognosis.

Melanoma can recur and metastasize. Local recurrence occurs at or near the original site and may result from incomplete removal of the primary tumor. The cells first metastasize from the primary tumor to the draining lymph node basin. These "in-transit" metastases are small tumors located in the skin between the original tumor and the lymph nodes. There is a much better prognosis for these local recurrences and in-transit metastases than there is for distant metastases.

Occasionally, metastatic melanoma is discovered with no known primary site; that is, no initial tumor is seen, and the cancer is diagnosed after it has spread. This occurs in 2% to 6% of all diagnosed melanomas. In most of these cases there is lymph node involvement, metastatic skin tumors, and sometimes internal spread. Careful examination of the skin, eyes, ears, nose, throat, and ano-genital area should be performed to look for a tumor.

Publication Review By: Stanley J. Swierzewski, III, M.D.

Published: 28 Feb 2007

Last Modified: 24 Aug 2015