With the sunny bank holiday weekend behind us this week, we’ll be looking at the reasons why applying that sun cream is extremely important for your health. It is a disease that has caused the death of many people including Bob Marley.
With malignant melanoma on the increase in the UK and its potentially fatal complications, this is a very important topic this week. The primary cause of malignant melanoma is ultraviolet light from the sun or other sources. Melanoma develops from the skin cells that contain a pigment known as melanocytes, most common in areas that are exposed to the sun. The UVB light from the sun is absorbed by the skin cells DNA and results in direct DNA damage; forming thymine-thymine, cytosine-cytosine or cytosine-thymine dimers. These melanocytes are found between the epidermis and the dermis layers. When the tumour cells extend into the epidermis and the papillary dermis the behaviour of the cells changes dramatically. This is known as the invasive radial growth phase where the cells grow quickly and acquire the ability to become invasive. This is followed by a vertical growth phase where it is now termed an invasive melanoma where cancerous cells can invade surrounding tissue, blood vessels and lymph. The appearance of these melanomas is an irregular outline that contains multiple colours (red, brown, black etc) which enlarge or evolve mole-like structures usually greater than 6mm in diameter.
Surgical treatment is used for melanomas in which an excisional biopsy is taken to remove the tumour. This then undergoes histological testing to check the diagnosis of melanoma. If the diagnosis is confirmed then a wider excision is made to remove tissue surrounding the lesion. This is to prevent reoccurrence. A margin of between 1-3cm is usually taken around and deep to the lesion. A partial-thickness skin graft is used to fill in the area as it can usually not be sutured back together. This skin graft is taken from a donor site on the patient such as a thigh. This is done using a dermatome, where the layer of the epithelium is grated off. This is then attached to a meshwork to increase the area it can cover before being applied to the site. The donor site epithelium will grow back from the sweat glands and hair follicles.