SKIN(EPIDERMAL) TUMORS

Benign tumors Melanocytic naevi Seborrhoeic warts (Basal cell papilloma) Keratoacanthoma

Premalignant tumors Actinic keratosis Intraepidermal carcinoma (Bowen’s disease)

Malignant tumors Basal cell carcinoma (BCC) Squamous cell carcinoma (SCC) Malignant melanoma Cutaneous T-cell lymphoma (Mycosis fungoides)

BENIGN TUMORSMELANOCYTIC NAEVI

Melanocytic naevi (moles) are localized benign tumours of melanocytes.

Based on the site of the aggregations of the abnormal melanocytes, Melanocytic naevi can be classified as:

1.

2.

a.

b.

c.

d.

e.

f.

CLINICAL FEATURES

Congenital melanocytic naevi

These are present at birth or appear in the neonatal period Less than 1 cm in diameter. Colour varies from brown to black or blue–black. With maturity some become protuberant and hairy and

Cerebriform appearance Congenital melanocytic naevi carry an increased risk of

malignant transformation, depending on their size (up to 10% in those with a diameter greater than 40 cm and less than 0.5% in those with a diameter less than 1.5 cm).

MELANOCYTIC TUMORS

NEVOCELLULAR NEVUS (MOLE) Benign tumor, contains proliferating melanocytes in clump(Nevus

cells) Related to sun exposure

Types: Junctional, Compound and Intradermal

Gross Picture: Uniform, tan to brown color Sharp, well circumscribed borders Tend to be stable in shape and size

Junctional Type Benign Occurs in Early Childhood Nests of pigmented nevus cells along basal cell layer Flat and pigmented lesion Junctional nevi develops into compound nevi Most melanocytic naevi of the palms, soles, mucous membranes

and genitals are of this type Malignant transformation is uncommon

Nevocellular nevus, Junctional type. A, In clinical appearance, lesions are small, relatively flat, symmetric, and uniform.

B, On histological examination, Junctional nevi are characterized by rounded nests of nevus cells originating at the tips of rete ridges along the dermoepidermal junction

COMPOUND NEVUS Nevus cells extend into underlying superficial dermis Both a Junctional and Intradermal component Usually occurs in children/ Adolescent These are domed pigmented nodules of up to 1 cm in

diameter. Raised, pigmented verruca like lesions They may be light or dark brown but their colour is more

even than that of junctional naevi. Most are smooth surface, but larger ones may be

cerebriform, or even hyperkeratotic and papillomatous Bear hairs.

Intradermal nevus are skin colored papule with nevus cells in the dermal layer

Nevocellular nevus, compound type. In contrast to the Junctional nevus, the compound nevus (A) is more raised and dome shaped. The symmetry and uniform pigment distribution suggest a benign process. Histologically (B), compound nevi combine the features of Junctional nevi (Intraepidermal nevus cell nests) with nests and cords of nevus cells in the underlying dermis.

DYSPLASTIC NEVI(B-K MOLES)

Nevi are larger and irregular Pigment variation is present Micros: Exhibit cytological and

architectural atypia Dysplastic Nevus Syndrome:

Autosomal Dominant (CMM1 gene on Chromosome I)

Often have multiple dysplastic nevi Increased risk of melanoma

Dysplastic nevus. A, The lesion often has a compound nevus component (right side of scanning field) and an asymmetric "shoulder" composed of a Junctional nevus component (left side of scanning field). The former correlates clinically with the more pigmented and raised central zone and the latter with the less pigmented, flat peripheral rim (inset)B, An important feature is the presence of cytologic atypia (irregularly shaped, dark-staining nuclei) at high magnification. The dermis underlying the atypical cells characteristically shows linear, or lamellar, fibrosis.

Intradermal melanocytic naevus withnumerous shaved hairs. Compound melanocytic naevus. No

recent change.

Junctional melanocytic naevus

PREMALIGNANT TUMORS

Actinic keratoses Discrete, rough-surfaced lesions crop up on sun-damaged skin. They are premalignant.

Factors affecting: Sun exposure. Fair complexions living near the equator Melanin protects Not seen in black skin. Albinos are prone to develop AK

Typical rough-surfaced actinic keratoses on the scalp

Presentation Middle-aged and elderly Living in temperate climates Younger people in the tropics The pink or grey rough scaling macules or papules of about 1 cm in

diameter

Complications Transition to an invasive squamous cell carcinoma Should be suspected if a lesion enlarges, becomes nodular, ulcerates

or bleeds.

TREATMENT

Freezing with liquid nitrogen or carbon dioxide Shave removal or curettage for large lesions and cutaneous horns. Multiple lesions, including subclinical ones, can be treated with 5-

fluorouracil cream Photo-dynamic therapy Lesions that do not respond should be biopsied.

MALIGNANT EPIDERMAL TUMOURS

Basal cell carcinoma (rodent ulcer) This is the most common form of invasive epidermal skin

cancer made of cells similar to basal cells. It crops up most commonly on the faces of the middle-aged or

elderly. Lesions invade locally and slow progression,no distant

metastasis More related to acute episodes of sunburn rather than

cumulative dose of UVR Chemicals like psoralen+UVR,arsenic intake for long time

predisposes to BCC Genetic predisposition –nevoid basal cell carcinoma syndrome,

xeroderma pigmentosum, albinism

Presentation Nodulo-ulcerative most common type. An early lesion is a small glistening

translucent, sometimes umbilicated, skin-colored papule that slowly enlarges.

Central necrosis, leaves an ulcer with an adherent crust and a rolled pearly edge

Coarse telangiectatic vessels often run across the tumor's surface.

Without treatment such lesions may reach 1–2 cm in diameter in 5–10 years.

TYPES Nodulo-ulcerative Cystic Cicatricial (morphoeic) Superficial (multicentric) Histological finding:islands and lobules

of basaloid cells in palisading arrangement

Basal cell carcinoma with markedTelangiectasia and ulceration

Early basal cell carcinoma with rolledopalescent edge and central crusting.

A grossly neglected basal cell carcinomainvading underlying bone

TREATMENT There is no single treatment of choice for all basal cell

carcinomas. Surgery(wide excision) Cryotherapy Radiotherapy Regular follow-up is advisable to detect local recurrences

when they are small and remediable

SQUAMOUS CELL CARCINOMA

This is a common tumour in which malignant keratinocytes show a variable capacity to form keratin.

Squamous cell carcinoma. Not a venous ulcer– too high up the leg, too raised and no signs of venous insufficiency

CLINICAL PRESENTATION AND COURSE

Tumours may arise as thickenings in an actinic keratosis or, de novo, as small scaling nodules,over damaged skin-scars,dermatitis,chronic granulomas,prolonged exposure to UVR

Carcinogens-inorganic arsenic or mineral oils Genetic –xeroderma pigmentosa Rapidly growing (over few months) anaplastic lesions Shallow Ulcers with a granulating base Indurated edge Squamous cell carcinomas are common on the lower lip and in the

mouth. Keratotic nodules Exophytic erythematous nodules Infiltrating firm tumors Regional lymphadenopathy Histology shows –horn cysts ,chr. Inflammatory cells , invading

strands of malignant keratinocytes

TREATMENT

After the diagnosis has been confirmed by biopsy, low-risk tumours should be excised with a 0.5-cm border of normal skin.

Wider excision (6 mm or more) , Mohs’ micrographic surgery is recommended for high-risk tumours.

Palpation of regional nodes is important in work-up and follow-up.

Radiotherapy is effective but should be reserved for the frail and elderly

Follow-up for up to 5 years is recommended for patients with recurrent disease and for those with high-risk tumours.

MALIGNANT MELANOMA

Predisposition-UVR ,xeroderma pigmentosa,displastic nevus syndrome,congenital melanocytic nevi

Clinical features Preceded by a superficial and radial growth phase, shown clinically

as the expansion of an irregularly pigmented macule or plaque Most are multicolored mixtures of black, brown, blue and pink. Margins are irregular with reniform projections and notches Malignant cells are at first are usually confined to the epidermis and

uppermost dermis Later they invade more deeply and may metastasize

Hallmarks of a malignant melanoma with its asymmetry, irregular borders and variations in colour. The pink Amelanotic nodule signifiesdeep dermal invasion

TYPES

Lentigo maligna melanoma Occurs on the exposed skin of the elderly. An irregularly pigmented, irregular shaped macule (a lentigo

maligna) enlarges slowly for many years. Followed by lentigo maligna melanoma(infiltrated nodules)

Superficial spreading melanoma Is the most frequent type. Its radial growth phase shows varied colors Is palpable A nodule coming up within such a plaque signifies deep

dermal invasion Has a poor prognosis

Acral Lentiginous melanoma Seen in palms and soles The invasive phase is signaled by a nodule coming up within an

irregularly pigmented macule or patch.

Nodular melanoma Appears as a pigmented nodule with no preceding in situ phase. It is the most rapidly growing and aggressive type.

Melanomas can also described by their colour, site and degree of spread.

Totally Amelanotic melanomas Are rare, and occur especially on the soles of the feet. Flecks of pigment can usually be seen with a lens.

Desmoplastic melanomas are rare. They are seen most often on the head, neck, palms and soles. They are sometimes Amelanotic.

Radial intra-epidermal growth phase of melanoma (1 and 2) precedes vertical and invasive dermal growth phase (3).

Histology of the differenttypes of melanoma invading the dermis

TREATMENT

Surgery Surgical excision, with minimal delay An excision biopsy They do not provoke

A minimum of 0.5 cm clearance for melanomas in situ and 1 cm clearance is required for all invasive melanomas.

Excision of 1 cm of normal skin around the tumour (or wound) for every millimeter of tumour thickness, up to 3 mm

Disseminated tumors-chemotherapy or radiotherapy