Benign and malignant epithelial lesions: Seborrheic keratosis: A common benign pigmented epidermal tumor occur in middle-aged or older persons more

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Jeffery Moody
5 years ago
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2 Benign and malignant epithelial lesions: Seborrheic keratosis: A common benign pigmented epidermal tumor occur in middle-aged or older persons more common on the trunk; but extremities, head and neck are also involved.

3 Gross: Round, exophytic, dark-brown, coin-like plaques, rough granular surface varying in size from mm to cms a stuck-on appearance.

4 Microscopic: Hyperkeratosis, acanthosis and papillomatosis. This lesion is purely epidermal. It is made-up of monotonous sheets of basaloid cells, showing variable melanin pigmentation with small keratin-filled cysts and pseudohorn cysts.

6 Actinic keratosis: (Suninduced dysplasia of keratinocytes) Gross: Multiple, scaly erythematous patches, having rough surface, occur in sun-exposed areas in fair-skinned people.

7 Microscopic: orthokeratosis alternating with parakeratosis and mild dysplasia confined to the basal cell layer. The dermis shows actinic elastosis and chronic inflammatory cellular infiltrate.

8 Hypertrophic variant shows psoriasiform epidermal hyperplasia Bowenoid variant shows full thickness squamous atypia with loss of orderly arrangement of the epidermis.

9 Bowen s disease: (Squamous cell carcinoma in-situ) Gross: Scaly erythematous plaques on sun-exposed skin in elderly patients.

10 Microscopic: (patterns: psoriasiform, atrophic, verrucous.etc.) Full thickness dysplasia of epidermal cells with mitotic figures, multinucleated cells and dyskeratosis, Pilosebaceous epithelium may be involved by atypical keratinocytes. Parakeratosis with loss of granular layer. Dermal inflammation.

11 Malignant epithelial tumours: Squamous cell carcinoma and basal cell carcinoma.

12 Melanocytic proliferations: Melanocytic nevi: are benign congenital or acquired neoplasm of melanocytes. Gross: Tan to brown, uniformly pigmented, small papules (5mm. or less), having well-defined rounded borders.

13 Microscopic:- Junctional nevi: Nests of round to oval cells, growing along the dermoepidermal junction, having uniform, round nuclei, inconspicuous nucleoli little or no mitotic activity.

15 Compound nevi: Nests and cords of nevus cells grow from the junctional zone into the underlying dermis.

Intradermal nevi: Junctional component disappear nevus cells appear intradermal only showing maturation: 1-superficial cells are large, melanized

16 Intradermal nevi: Junctional component disappear nevus cells appear intradermal only showing maturation: 1-superficial cells are large, melanized and grow in nests 2- deeper cells are smaller, having no melanin and grow in cords or single cells. 3-deepest cells are fusiform and grows in fascicles.

17 Dysplastic nevi: Gross: Are larger and numerous; appear as flat macules or slightly raised plaques, having variable pigmentation and irregular borders.

18 Microscopic: Appear as compound nevi having junctional and dermal components.

19 Microscopic Junctional component shows large cell nests exhibiting fusion and bridging with adjacent nests.

20 Microscopic The dermal component shows sparse lymphocytic infiltrate, melanin incontinence and linear fibrosis surrounding epidermal nests of melanocytes.

21 Microscopic Nevus cells show irregular angulated hyperchromatic nuclei.

Gross: A nodule, with striking variations in pigmentation, including

22 Melanoma: A malignant tumor, its incidence is highest in areas where sun exposure is high and much of population is fair-skinned. Gross: A nodule, with striking variations in pigmentation, including shades of black, brown, red, dark blue and grey, with irregular notched borders.

23 Melanoma cells are large, epithelioid-like or spindle, having large nuclei, with irregular contours, peripheral chromatin clumping prominent eosinophilic nucleoli

25 Radial growth phase (in situ): malignant cells grow as poorly formed nests or as individual cells at all levels of the epidermis (pagetoid spread); the dermis shows brisk lymphocytic infiltrate

26 Vertical growth phase: the tumor grows downwards into the deeper dermal layers lacking cellular maturation.

28 Warning signs in a pigmented lesion: Rapid enlargement in size irregular borders itching or pain variegated colour.

29 Metastasis in melanoma is predicted by: 1-Measuring the depth of invasion in millimeters from the top of granular layer (Breslow thickness)

30 2-Tumours with high mitotic rate.

Pathology of the skin. 2nd Department of Pathology, Semmelweis University

Pathology of the skin. 2nd Department of Pathology, Semmelweis University Pathology of the skin 2nd Department of Pathology, Semmelweis University Histology of the skin Epidermis: Stratum corneum Stratum granulosum Stratum spinosum Stratum basale Dermis: papillary and reticular