How to detect a skin cancer (Part - I) ?
How to detect a malignant melanoma ?
Malignant melanoma - an overview
Melanoma results from an uncontrolled proliferation of pigment forming cells, the melanocytes. In adult skin, these cells reside in the basal layer of epidermis (the upper layer of skin), in the dermis (the lower layer of skin) and in the oil secreting sebaceous glands.
The most challenging aspect in melanoma cure is early detection and excision at a curable stage. Tumor thickness and level of penetration into the skin are the major factors that determine the progression and clinical outcome of melanoma. The lesser the tumor penetrates into the skin, better are the chances of recovery.
Dysplastic nevi or atypical moles, the main precursors of melanoma are larger in size than common moles (>5 mm diameter), have an uneven surface that is flat at one place and raised at another, have blurred and irregular margins and exhibit a variegation in color ranging from tan to dark brown or black. They occur mainly on the trunk
The various common subtypes of malignant melanoma include the following :
1. Lentigo maligna melanoma
It is a flat, freckle like patch of an irregular shape with differing shades throughout, that occurs on sun exposed parts of skin, most often in elderly individuals with a sun damaged, thin, parchment like skin. It grows radially on the skin increasing in diameter, that may eventuate into invasive melanoma that penetrates into deeper layers of skin and begins to spread.
2. Superficial spreading melanoma
Being the most common type of melanoma, it occurs most commonly on the legs of women and the upper backs of men. It begins as a dark brown or black patch or as an area of increased darkening in a preexisting mole which exhibits variegation of pigment. Different shades of brown, black, dark blue, grey and pink are spread haphazardly in a single lesion. As it grows, the surface becomes shiny, glossy, with irregular borders, indentations or notches or scalloping of margins.
3. Nodular melanoma
Another common type of melanoma that develops on the trunk, head and neck, nodular melanoma exhibits a rapid growth, does not spread on skin surface, but penetrates the skin barrier early. It appears as a uniform blueberry shaped nodule and its surface has a thundercloud grey appearance.
4. Acral lentigenous melanoma
This is the most common subtype in dark skinned individuals. Sole of the foot being the most common site, it also occurs on the palms and beneath the nail plate. It begins as a tan, brown or black flat lesion showing a mixture of colors from blue to black and with irregular borders. Later on nodules may develop. It is the most aggressive form of melanoma often associated with a poor outcome.
Subungual melanoma is a variant of the acral lentigeous melanoma that develops as a brown to black discoloration in the nail bed of great toe or thumbnail. Hutchinson's sign, the presence of pigmentation on the posterior nail fold behind the nail is an ominous finding and signifies an advanced stage.
Cancerous change in a mole
Is it a mole or a melanoma
A common mole is an aggregation of melanocytes in the upper or lower layers of skin. It develops after birth, slowly enlarges symmetrically, stabilizes and persists or regresses later in life. Common moles usually have a homogeneous surface and coloration pattern, round or oval shape, regular outlines and a relatively sharp border.
The major characteristics that should raise a suspicion of melanoma follow the ABCDE rule.
- A for asymmetry of the lesion.
- B for border characteristics (notched, scalloped and irregular).
- C for color (mottled haphazard display of all shades of brown, black, grey, pink, white and blue).
- D for diameter >6 mm (greater than a pencil eraser).
- E for evolution or growth of the lesion.
In advanced stages the normal skin cleavage lines might be lost or obliterated. Pattern of skin coloration is the single most important attribute for detection of a melanoma. Focal black areas, if newly developed, should raise a suspicion of melanoma. Changes of regression correspond to focal areas of white, grey and pink.
The most suspicious sign suggestive of melanoma is a persistently changing pigmented lesion.
When to raise an alarm
The appearance of a newly pigmented lesion, particularly in an individual beyond the age of 30 to40 years and on an area of the body without similar lesions should raise concern.
For self examination, choose a well lit room, would be better if it receives natural sunlight, and examine every inch of your skin standing in front of the mirror. Use a full length mirror for front examination and a smaller back mirror to check the dorsum of your torso. If you discover any suspicious lesion, then immediately fix an appointment with a physician.
Melanoma progression should be suspected when a preexisting mole shows the following features:
- Increase in size - A long standing mole suddenly shows a rapid growth within a few days. Increase in size occurs in all directions. The moles become wider and thicker.
- Change in color - The common mole becomes darker. The color change is patchy, with some areas showing darker shades, while others are lightly pigmented. Sometimes malignant melanoma does not show pigment and such a lesion is called an amelanotic melanoma.
- Bleeding - The skin overlying the mole becomes fragile, ulcerated and often breaks down with minor injury and starts bleeding.
- Evidence of local spread - Tumor cells gradually invade the surrounding skin to produce a dark halo. The area around the mole shows a dark hue. Gradually the cancer cells permeate the skin barrier and spread via lymphatics to the surrounding skin producing satellite nodules a little distance away from the primary tumor. Gradually more satellites develop at greater distances.
- Enlarged regional lymph nodes - Appearance of small rounded swellings or lymph nodes near the initial lesion indicate that the growth has become cancerous.
When to suspect a melanoma
- Appearance of a new pigmented lesion in an individual beyond third or fourth decade.
- Increase in size, darkening, itchiness or bleeding in a preexisting mole.
- Satellite nodules developing around a mole.
- Appearance of small rounded swellings or lymph nodes near the mole.
Symptoms of a melanoma cancer
Melanoma is not painful. The cancerous mole itches a lot. There may be swellings in the groin, underarms or neck according to the region of the primary tumor.
In late cases, the individual may experience weight loss, difficulty in breathing due to the tumor spreading to the lungs or jaundice due to liver involvement.
ABCDE rule to detect a malignant melanoma
Cancer signs in a mole
Asymmetry of the lesion
Lesion has a haphazard appearance
Notched, scalloped or irregular borders
Mixture of colors with shades of brown, black, grey, blue and pink
Greater than 6 mm
Rapid growth of lesion
Appearance of a melanoma on self examination
- Site - Most melanomas develop on exposed areas or on palm or sole of feet. They may also appear in the mouth or anus.
- Color - Melanoma may show any color from different shades of brown and black. Darker the color, more are the chances of malignancy.
- Temperature and Tenderness - A malignant melanoma has a normal skin temperature and is painless on touch.
- Surface - When small, the surface is smooth, but as it attains larger size, small ulcers and crusts develop and it becomes fragile and starts bleeding easily. The surface of a big melanoma looks wet, soft and boggy.
- Consistency - The tumor feels firm. The small satellite nodules may feel hard to touch.
- Mobility - The tumor moves with the skin as it arises from the skin. It can be easily lifted up from the deeper structures.
- Surrounding skin - A dark grey halo or satellite nodules may be seen in the surrounding skin.
- Regional lymph nodes - Neck, underarm area and groin should be examined for any newly developed swellings.
How does a melanoma look like ?
Melanomas are curable if diagnosed at an early stage. Any kind of fear, denial or shame can make the disease spread and reach advanced stages.
Do periodic self examinations to look for any new suspicious lesion or any change in a preexisting mole. Increase in size, change in color, shape, itchiness or bleeding in a preexisting mole demands immediate medical consultation.
Your cure lies in your own hands. Some amount of self vigil can help treat this dreaded disease.