Cutaneous Malignancies MBChB IV

Outcomes for this lecture After this lecture the student should be able to:   Name the 5 most common skin malignancies Discuss the aetiology of skin cancer Recognise and describe the clinical presentations of the different types of basal cell carcinoma, squamous cell carcinoma, solar keratosis, melanoma and keratoacanthoma Name the risk factors for the development of melanoma Explain the nature and implications of dysplastic nevi Name the danger signs that may be present in pigmented lesions that can point to the diagnosis of melanoma (ABCDE) Describe in detail the procedure that has to be followed to confirm the diagnosis of a suspicious looking pigmented lesion Broadly discuss the management of the different types of skin cancer

Most Common Forms of Skin Cancer Basal cell carcinoma Solar keratosis Squamous cell carcinoma Melanoma Keratoacanthoma (?) Many others

Etiology of Skin Cancer Ultraviolet light – UVB: Squamous cell CA Basal cell CA – UVA: Melanoma Genetic – predisposition (Celtic decent) albinism syndromes Human papilloma virus (genital) Ionic irradiation Chemicals – Arsenic Coal tar Heat

Basal Cell Carcinoma Most common infiltrating malignancy in humans Very slow growth tempo Different types Practically never metastasizes Often multiple Never on mucous membranes

Basal Cell Carcinoma: Types Nodular Ulcerative Superficial spreading Sclerosing Pigmented

Management: Therapeutic Curettage and cautery Surgical excision Radiotherapy Intralesional interferon Topical imiquimod Always confirm histologically Never freeze!

Management: Advice / Information Explain prognosis Sun exposure Sunscreen creams Self examination of rest of skin Education of children

Management: Follow-up 6-monthly for 4 years Scar + rest of skin

Solar Keratosis Extremely common Small squamous carcinoma, limited to the epidermis, not full thickness Not “pre-malignant” Pink base, whitish hyperkeratosis on top No fleshy component palpable

Solar Keratosis: Treatment Cryotherapy Curettage 5-Fluorouracil ointment Imiquimod cream Photodynamic therapy Seldom surgery necessary

Squamous Cell Carcinoma Second most common infiltrating skin CA Grows faster than BCC, more aggressive Low incidence of metastases (lymph nodes) Common on mucous membranes (smoking) Majority begin as solar keratoses

Management Surgical excision still first choice Radiotherapy Topical imiquimod only for in-situ lesions Lymph node dissection for metastases Never freeze

Melanoma Most malignant tumour in humans Very common (epidemic) Caused by high exposure to UVA in childhood ?Role of sunscreen creams Familial predisposition (genetic defects) Metastasizes early, rapidly

Melanoma: Risk Factors More than 30 melanocytic nevi Three or more dysplastic nevi Light skin that sunburns easily Three or more severe sunburn episodes as a child Family history of melanoma Previous melanoma Exposure to sunbed tanning

Melanoma: Risk Factors NB: Dysplastic nevi and common melanocytic nevi seldom (if ever) precursors of melanoma

Melanoma: Clinical Appearance A: Asymmetry B: Border – irregular C: Colours – different shades of brown and black D: Diameter – > 6mm E: Evolution – changes in appearance

Melanoma: Types Superficial spreading Nodular Acral lentiginous Lentigo maligna Other (e.g. amelanotic)

Melanoma: Diagnosis Clinically: Changing pigmented lesion Biopsy: Conservative excision of whole lesion with 1mm edge of normal tissue If lesion too big: Incision biopsy of thickest / blackest part, including edge Never punch biopsy Never primary wide excision based on a clinical diagnosis!!!

Melanoma: Treatment Wide surgical excision according to Breslow thickness of tumour Sentinel lymph node dissection for tumours between 1mm and 4mm thick Therapeutic lymph node dissection if positive

Melanoma: Investigations Exclude metastases Examine the rest of the skin!!

Melanoma: Follow-up 6-Monthly, life long Look for recurrence, metastases, new lesions

Patients With Many Moles Follow up photographically Dermatoscopy Prophylactic excision of moles not indicated