1. 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)

2. Benign tumors Melanocytic 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.

3. 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).

4. Melanocytic tumors

5. 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

6. 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

7. 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

8. Nevocellular nevus, compound type
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.

9. 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.

11. Intradermal melanocytic naevus with
numerous shaved hairs.
Compound melanocytic naevus. No recent change.
Junctional melanocytic naevus

12. 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

13. 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.

14. 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.

15. 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

16. 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.

17. types Nodulo-ulcerative Cystic Cicatricial (morphoeic)
Superficial (multicentric)
Histological finding:islands and lobules of basaloid cells in palisading arrangement
Basal cell carcinoma with marked
Telangiectasia and ulceration
Early basal cell carcinoma with rolled
opalescent edge and central crusting.
A grossly neglected basal cell carcinoma
invading underlying bone

18. 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

19. 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

20. 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

21. 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.

22. 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 signifies
deep dermal invasion

23. 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

24. 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.

25. Radial intra-epidermal growth phase of melanoma (1 and 2) precedes vertical and invasive dermal growth phase (3).
Histology of the different
types of melanoma invading the dermis

26. 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