What is the difference between Melanoma and Carcinoma?

This is a very common question and fairly simple to understand.

If you imagine that the skin is made up of a few different layers. There are seven in total, three are the main layers and five are sublayers.

The three main layers are-


Epidermis (with 5 sublayers)
This outer layer, no thicker than a sheet of paper, both shields you from the world and presents you to it.

Dermis
This thick middle layer makes up most of your skin. It contains collagen and elastin — fibres that give strength, structure and elasticity. 


Hypodermis/Subcutaneous layer
This layer, which is mainly fat, is the source of nerves and blood vessels as well as the roots of your hair follicles, oil glands and sweat glands.

Melanoma
As you can tell from the diagram, the Melanocyte (a type of skin cell), lies in the lowest part of the dermis and is responsible for the production of Melanin (pigment) in your skin. 
This is where melanoma begins and is usually a result of sun damage (tanning). 
Possible signs of melanoma include a change in the appearance of a mole or pigmented area of the skin. I will be posting on how to keep an eye on these moles shortly.
Melanoma is the rarest form of skin cancer, but it is also the most aggressive and is most likely to spread to other parts of the body. 
The Skin Cancer Foundation says South Africans are diagnosed every year with the highest rate of melanoma skin cancer in the world! 
All skin cancers can occur anywhere in the body, but melanoma is most common in skin that is exposed to sunlight, such as the face, neck, hands and arms.


Carcinoma
There are two types of Carcinoma - Squamous cell Carcinoma and Basal cell Carcinoma. 
They form in the upper and middle parts of the epidermis, respectively. Both are classified as 'nonmelanoma' and rarely spread to other parts of the body. 
Possible signs of nonmelanoma include unusual changes in the skin, such as areas that are small, raised, smooth or red, or skin that is rough, red and scaly.

Image courtesy of  http://www.heartspring.net/art_skin_layers_diagram.html