Skin tumors

Melanocytic naevi Melanocytic naevi are normal, benign proliferations of melanocytes. Although the risk of a naevus evolving into a melanoma is extremely small, melanocytic naevi are both risk factors for melanoma and precursors of melanoma. Cause is unknown but maybe related to abnormalities of the normal migratory pattern of the melanocytes during development. Whites have an average of 15 to 40 nevi on their skin. Frequently contain hair.

Clinical features Acquired melanocytic naevi Junctional naevi- are circular and macular, their color may be from mid- to dark brown and may vary within a single lesion. Compound and intradermal naevi- similar to one another in the appearance, both are nodules of upto 1cm in diameter. Intradermal naevi are less pigmented than compound naevi. So, they are pigmented lesion with a papillomatous surface. Dysplastic nevus (atypical mole) – May arise sporadically – Controversial on whether they may develop into a malignant melanoma – Usually>6mm; variegated in color with an erythematous background; irregular borders – May be associated with the dysplastic nevus syndrome(majority develop malignant melanoma) Autosomal dominant syndrome with >100 nevi on the skin

Melanocytic naevi

Treatment Do not require treatment(excision)except when malignancy is suspected or when it become repeatedly become inflamed or traumatised. Sometimes excision is done for cosmetic purpose only.

Seborrhoeic Warts(Basal cell warts) Common bening epidermal tumors. Appear oily, but they have nothing to do with sebaceous glands and hence k/a seborrhoeic.

Clinical Features Rare before the age of 35 Initially they may become visible as macular pigmented area They may become markedly elevated and are most commonly found on trunk and face Coin-like, macular to raised verrucoid lesion with "stuck-on" appearance

Seborrhoeic Warts(Basal cell warts)

Treatment a. Cryotherapy b. Curettage e. Shave biopsy/excision

Keratoacanthoma Male predominance Rapidly growing, benign keratinocyte tumor with a central keratin plug a. Grows within 4 to 6 weeks b. Develops in sun-exposed areas c. Mimics a well-differentiated squamous cell carcinoma Regresses spontaneously with scarring usually within 6 months Excision is recommended

Keratoacanthoma

MALIGNANT TUMORS OF THE SKIN

Basal Cell Carcinoma Most common human cancer. Caused by chronic exposure to ultraviolet light Occurs in sun-exposed areas a. Inner canthii of the eye, upper lip b. Very general rule of thumb is that BCCs favor upper lip and higher.

Clinical presentation Raised papule or nodule with a central necrosis ( nodulo- ulcerative form, the commonest form) Sides of the crater are surfaced by telangiectatic vessels. Locally aggressive, infiltrating cancer that does not metastasize a. Tumor is stromal dependent, hence precluding metastasis, b. Arises from the basal cell layer of the epidermis c. Multifocal in origin This makes it difficult to get free margins after surgery d. Cords of basophilic-staining basal cells infiltrate underlying dermis Rodent ulcer is commonly used for slowly expanding ulcerative BCC

Basal Cell Carcinoma

Diagnosis Punch biopsy or shave biopsy Treatment Varies with location and size of the cancer Options include topical 5-fluorouracil. cryotherapy, curettage and electrodesiccation, surgical excision, radiation (usually in elderly).

Squamous Cell carcinoma Risk factors a. Excessive exposure to ultraviolet light (most common) b. Actinic (solar) keratosis c. Arsenic exposure d. Scar tissue in a third-degree burn e. Orifice of chronically draining sinus tract f. Immunosuppressive therapy

Clinical Presentation Scaly to nodular lesions a. Nodules are often ulcerated. b. Majority occur in sun-exposed areas of die body. Examples—ears, lower lip, dorsum of the hands Very general rule of thumb is that SCCs favor lower lip. Usually well differentiated Minimal risk for metastasis

Squamous Cell carcinoma

Treatment a. Varies with location and size of the cancer b. Options include topical 5-fluorouracil, cryotherapy, curettage and electrodesiccation. surgical excision, radiation (usually in elderly),

Malignant Melanoma Epidemiology – a. Malignant tumor of melanocytes – b. Most rapidly increasing cancer worldwide More common in whites than blacks Leading cause of death due to skin cancer Median age at diagnosis is 53 years.

Risk factors a. Exposure to excessive sunlight (UVA and UVB) at an early age Single most important risk factor b. History of a family member with melanoma c. Use of tanning booths d. Dysplastic nevus syndrome e. History' of melanoma in first- or second-degree relative f. Xeroderma pigmentosum

Malignant Melanoma

Invasive melanomas are preceded by a radial and vertical growth phases. Radial growth phase a. Initial phase of invasion b. Melanocytes proliferate (1) Laterally within the epidermis (2) Along the dermoepidermal junction (3) Within the papillary dermis c. No metastatic potential in this phase Vertical growth phase a. Final phase of invasion b. Malignant cells penetrate the underlying reticular dermis, c. Potential for metastasis

‘Types of malignant melanoma a. Superficial spreading melanoma (1) Most conmmon type (70% of cases) (2) Develops on lower extremities, arms, and upper back b. Lentigo maligna melanoma (4-10% of cases) (1) Comnon in the elderly population (2) Extension of lentigo maligna (intra epidermal lesion) into the dermis (3) Occurs on parts of the face most exposed to the sun (4) Least likely to have a vertical phase c. Nodular melanoma (15-30% of cases) (1) No radial growth phase (2) Can be found in any sun-exposed area Most often the trunk (3) only vertical phase (4) Poor prognosis d. Acral lentiginous melanoma (2-.S% of cases) (1) Not related to sun exposure (2) Located on the palm, sole, or beneath the nail Often confused with a subungual hematoma (3) Most often occurs in Asians and blacks (4) Poor prognosis

Depth of invasion best determines biologic behavior. ABCD criteria for malignancy – a. Asymmetry of shape – b. Border irregularity – c. Color variation – d. Diameter > 6 mm

Prevention a. Sunscreen > 15 SPF (controversial) Prevention for UVA and UVB light b. Protective clothing

Treatment a. Excision of entire lesion and surrounding normal tissue Sentinel lymph node biopsy to determine stage b. More extensive disease Immunotherapy; irradiation