Melanoma

Question 1

Define

Answer 1

DEFINITION: malignancy arising from neoplastic transformation of melanocytes, the pigment-forming skin cells. The leading cause of death from skin disease.

Question 2

Causes

Answer 2

DNA damage caused by ultraviolet radiation leads to neoplastic transformation

50% arise in existing naevi

50% arise in previously normal skin

FOUR histopathological types

• Superficial Spreading (70%)
• Arises in a pre-existing naevus, expands in a radial fashion before a vertical growth phase

Nodular (15%)

• Arises de novo
• AGGRESSIVE
• NO radial growth phase

Lentigo Maligna (10%)

• More common in ELDERLY with sun damage
• Large flat lesions
• Progresses slowly
• Usually on the face

Acral Lentiginous (5%)

• Arise on palms, soles and subungual areas
• Most common type in NON-WHITE populations

Question 3

Epidemiology

Answer 3

Steadily increasing in incidence

WHITE races have 20 x increased risk compared to non-whites

Question 4

Symptoms

Answer 4

Change in size, shape or colour of a pigmented skin lesion

Redness

Bleeding

Crusting

Ulceration

Question 5

Signs

Answer 5

ABCDE criteria for examining moles:

A - asymmetry

B - border irregularity

C - colour variation

D - diameter > 6 mm

E - elevation/evolution

Question 6

Investigations

Answer 6

Excisional Biopsy - histological diagnosis and determination of Clark’s Levels and Breslow Thickness (two methods of determining the depth of penetration of a melanoma)

Lymphoscintigraphy - a radioactive compound is injected into the lesion and images are taken over 30 mins to trace the lymph drainage and identify the sentinel nodes

Sentinel Lymph Node Biopsy - check for metastatic involvement

Staging - using ultrasound, CT or MRI, CXR

Bloods - LFTs (because the liver is a common site of metastasis)