MALIGNANT MELANOMA
OutlineIntroduction 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 presentMALIGNANT MELANOMA
A tumour arising from melanocytes of the basal layer of the epidermisLess commonly – uveal tract (eye) and meningeal membranesAETIOLOGY
The cause is unknown. Excessive exposure to sunlight Genetic predispositionRISK FACTORS FOR MELANOMA
Large numbers of benign naevi Clinically atypical naevi Severe sunburn Early years in a tropical climate Family history of MMClinical 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 sensationAMERICAN ‘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 malanomaSUPERFICIAL 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 irregularNODULAR
Commoner in males Trunk is a common site Rapidly growing Usually thick with a poor prognosis Black/brown nodule Ulceration and bleeding are commonACRAL 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 componentSUBUNGAL MELANOMA
RareOften diagnosed late – confusion with benign subungal naevus, paronychial infections, traumaHutchinson’s sign – spillage of pigment onto the surrounding nailfoldLENTIGO 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 developsDDx
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