melanomas

MALIGNANT MELANOMA

Outline
Introduction Aetiology Types Invasion and Metastasis Risk Factors Diagnosis and Staging Treatment and Prevention

Skin:Epidermis - Melanocytes

Melanocytes:In stratum basalePale “halo” of cytoplasmNeural crestProduce melanin and pass it on to nearby keratinocytesMelanin covers nuclei of nearby keratinocytesSkin colour depends on melanocytes activity, rather than the number present

MALIGNANT MELANOMA

A tumour arising from melanocytes of the basal layer of the epidermisLess commonly – uveal tract (eye) and meningeal membranes

AETIOLOGY

The cause is unknown. Excessive exposure to sunlight Genetic predisposition

RISK FACTORS FOR MELANOMA

Large numbers of benign naevi Clinically atypical naevi Severe sunburn Early years in a tropical climate Family history of MM



Clinical features
Occur anywhere on the skin Females (commonest is lower leg) Males ( back). Early melanoma is pain free. The only symptom if present is mild irritation or itch.

AIDS IN CLINICAL DIAGNOSIS

GLASGOW SYSTEM Major: Change in size Irregular pigment Irregular outline Minor: Diameter >6mm Inflammation Oozing/bleeding Itch/altered sensation
AMERICAN ‘ABCDE’ SYSTEMAsymmetryBorder Colour DiameterEvolution

Evolving; a mole or skin lesion that looks different from the rest or is changing in size, shape, or color

TYPES OF MELANOMA

Superficial spreading Malignant melanoma Nodular melanoma Letingo maligna melanoma Acral malanoma

SUPERFICIAL SPREADING

The most common type of MM in the white-skinned population – 70% of casesCommonest sites – lower leg in females and back in malesIn early stages may be small, then growth becomes irregular

NODULAR

Commoner in males Trunk is a common site Rapidly growing Usually thick with a poor prognosis Black/brown nodule Ulceration and bleeding are common

ACRAL LENTIGINOUS MELANOMA

In white-skinned population this accounts for 10% of MMs, but is the commonest MM in nonwhite-skinned nations Found on palms and soles Usually comprises a flat lentiginous area with an invasive nodular component

SUBUNGAL MELANOMA

RareOften diagnosed late – confusion with benign subungal naevus, paronychial infections, traumaHutchinson’s sign – spillage of pigment onto the surrounding nailfold

LENTIGO MALIGNA MELANOMA

Occurs as a late development in a lentigo maligna Mainly on the face in elderly patients May be many years before an invasive nodule develops


DDx
Superficial spreading melanomas Benign melanocytic naevi. Nodular melanomas Vascular tumor Histiocytoma Latingo maligna melanoma Seborrhic keratoses

PROGNOSTIC VARIABLES

The Breslow thickness is the single most important prognostic variable (distance in mm of the furthest tumour cell from the basal layer of the epidermis)
Breslow depth
5 year survival
In situ
95-100%
<1mm
95-100%
1-2mm
80-96%
2.1-4mm
60-75%
>4mm
50%



Scalp lesions worse prognosis, then palms and soles, then trunk, then extremeties Younger women appear to do better than either men at any stage or women over 50 Ulceration of the tumour surface is a high risk factor

MANAGEMENT

Surgical resection of tumour MOHS technique Lymph node dissection Chemotherapy Radiotherapy Immunotherapy

Prevention

Reduce risk factor exposure: Covering up (sunscreen, sunglasses, clothes) Avoidance (less time in sun) Screening (possibly feasible)