Malignant Melanoma of the Foot

Definition

Malignant Melanoma is a cancer of the skin and is defined as an out of control growth of the skin cells that produce the melanin.  Normal skin cells, called melanocytes, contain melanin which provides color to our skin. The more melanin present in the skin, the darker the skin. Melanin provides protection against UV waves from the sun and their damaging effect. Melanoma is usually from overexposure to UV waves of the sun.

Literature suggests there are approximately 160,000 new cases of malignant melanoma are diagnosed each year and approximately 48,000 deaths are attributed to melanoma each year.

Classification
Malignant Melanoma’s severity is based on the depth of penetration into the epidermis and dermis. The depth of severity are defined by two classification systems:

  1. Clark”s classification describes the depth of penetration one sees on a histological slide. The depths are classified from 1-5 depending on the level progressing from superficial epidermis (level 1) to deep dermis/subcutaneous tissue (level 5).
  2. Breslow’s classification stages the tumor based on the measured depth of penetration of the growth from the epidermis into the dermis/subcutaneous tissue. The measurement is from level 1 (.75mm) to level 5 (Greater than 4mm).

The malignancy can spread via the blood stream to other parts of the body and settle in the liver and lung.

Characteristics
Malignant melanoma presents as a dark or discolored lesion. Other characteristics included a raised surface, friability (easy to bleed), pain or burning.  In general, soft tissue masses, and melanoma, can be best described based on the ABCD”s:

A: Asymmetry, or uneven shaped with one side larger than the other.

B: Boarders, irregular which present jagged and not smooth.

C: Color, changes from the normal skin color with usually a mix of color.

D: Diameter, a melanoma will enlarge over time whereas a “beauty mark” will remain the same size.

There are four types of Melignant Melanoma:

  1. Superficial spreading melanoma (70% of diagnosed cases)
  2. Nodular melanoma (15% of diagnosed cases)
  3. Lentigo maligna melanoma (10% of diagnosed cases)
  4. Acral lentiginous melanoma (5% of diagnosed cases)

Treatment
Biopsy of the skin lesion is the only definitive diagnosis for malignant melanoma. Once submitted to pathology an accurate diagnosis can be performed.  Following staging of the lesion, your Podiatric Physician can coordinate appropriate treatment.