Malignant Melanoma Flashcards
What is the role of melanocytes?
Produce melanin - a protein that helps protect against harmful UV exposure.
Number of melanocytes in darker vs white skin?
Melanocytes are found in equal numbers in different skin tones. However, darker skin produces more melanin.
Therefore, damage caused by UV exposure is more likely in white skin compared to dark-brown or black skin.
Where is melanoma in situ confined to?
Epidermis
When melanocytes grow in a non-cancerous way, what do they result in?
- Moles (benign melanocytic naevi)
- Freckles (lentigines and phelides)
What are the 4 common subtypes of melanoma?
1) Superficial spreading melanoma
2) Nodular melanoma
3) Lentigo maligna melanoma
4) Acral lentiginous melanoma
What is the most common type of melanoma?
Superficial spreading melanoma (70% of cases)
Where does superficial spreading melanoma typically affect?
- arms
- legs
- back
- chest
Describe growth of superficial spreading melanoma
1) Malignant melanoma cells have a longer ‘in situ’ phase (months to years).
2) Initially grows horizontally (radial growth phase), presenting as a flat, irregularly pigmented lesion that slowly enlarges.
3) As invasion continues, the growth may become vertical.
What is the most aggressive type of melanoma?
Nodular
Growth of nodular melanoma?
Malignant melanoma cells invade vertically, presenting as a nodule that grows rapidly (weeks to months).
What type of melanoma often bleeds or ulcerates?
Nodular
What is the precursor lesion to lentigo maligna melanoma?
Lentigo maligna
What is lentigo maligna directly related to?
Sun exposure
Typical age that superficial spreading vs lentigo maligna affects?
Superficial spreading - younger people
Lentigo maligna - older people
Where does acral lentiginous melanoma typically appear?
Palms, soles or under the nails.
Often diagnosed at a late stage due to their location.