this is a class lecture of Pathology for undergraduate students based on the topic 'Diseases of skin' following Robbibs Pathologic basis of disease. The lecture is prepared by Dr. Umme Kulsum Munmun, Assistant Professor for the 4th year students of Chandpur Medical College, Chandpur, Bangladesh. This was previously delivered to 4th year students of Cumilla Medical College. It contains a short description of the common diseases of skin and their pathology. Hopefully this will be helpful for all undergraduate medical students.

1. DISEASES OF SKIN
Dr. Umme Kulsum Munmun
Assistant Professor,
Department of Pathology,
Chandpur Medical College

8. Diseases of Skin
 Inflammatory dermatoses:
- Urticaria (hives)
- Eczematous dermatitis
- Erythema multiforme

9. Inflammatory Dermatoses
 Hives
 Urticaria (wheal)
 Generalized
 Allergic reaction
 Bee sting
 Medications
 IgE mediated
 Histamine release
 Vascular dilation
 Fluid in tissues

10. Eczema, ‘Boiling Over’
 Allergic contact dermatitis
 Atopic dermatitis
 Drug related atopic dermatitis
 Photoeczematous dermatitis
 Red, papulovesicular, oozing and crusted lesions
 Scaling plaque, if persistent

11. Chronic Inflammatory
Dermatoses
 Persistent, months to years
 Skin is roughened due to excessive or abnormal scale
formation and shedding
 Thickening
 Scaling
 Roughening
 Variable inflammation of dermis

12. Chronic Inflammatory
Dermatoses
 Seborrhoec dermatitis – regions with high density
of sebaceous glands, scalp etc

13. Psoriasis
 Ag/Ab reaction?
 Knees, elbows,
scalp, lumbosacral
areas, intergluteal
cleft, glans
 Whole body is
pretty bad
 At areas of trauma
 Pink to salmon –
colored plaque
covered by loosely
adherent silver
white scale

14. Lichen Planus
 Resolving spontaneously
1 to 2 years after onset
 Flat topped, pruritic,
pink-purple, polygonal
papule with white
lacelike patterns of lines
 Papules may coalesce to
form plaques

15. Lupus Eyrthematosis
 Autoimmune
 Two forms
 Systemic
 Discoid (skin only)
 Systemic problems
 Kidney failure
 Vasculitis and
 DVT with emboli
 Antibodies in serum
 Anti-DNA
 Other nuclear

16. Infections of Skin
 Bacterial
 Impetigo – Superficial bacterial infection
 Abscesses
 Acne – occlusion of sebaceous glands
 Fungal
 Ringworm
 Viruses
 Verurcae (warts), molluscum contagiosum, smallpox

17. Impetigo

18. Acne

19. Verrucae (Warts)
 Squamoproliferative disorders
 Caused by HPV
 Gray white to tan papules
 Verrucae vulgaris- most common, occur
anywhere, frequently on hands, periungual
areas
 Verrucae plana or fat wart- face, hands
 Verrucae plantaris- sole
 Verrucae palmaris- palm
 Condyloma acuminatum (veneral wart) –
genital region

20. Verrucae (Warts)

21. Disorders of Epidermal
Maturation
 Icthyosis

22. Epithelial tumours
 Benign:
- Seborrheic keratosis
- Acanthosis nigricans
- Keratoacanthoma
- Fibroepithelial polyp
- Epidermal cyst
Seborrheic Keratosis

23. Epithelial tumours
 Premalignant:
- Actinic Keratosis

24. Epithelial tumours
Malignant

25. Basal Cell
Carcinoma
 The most common malignancy
we suffer from.
 Solar exposed skin.
 Common site- above imaginary
line joining angle of mouth and
pinna
 Pearly papule
 Raised edges
 Maybe central ulceration

26. Basal Cell Carcinoma
 Slow growing tumors
 Do not metastasize usually
 Recognized at early stage
 Cured by local excision
 A small number (0.5%) of tumors are locally
aggressive
 Also called rodent ulcer

27. Squamous Cell Carcinoma
 Arises from
differentiated
squamous epithelium
 Sun exposed
 UV
 Metastasizes

28. Squamous Cell
Carcinoma
 Cells produce keratin
pearls
 Invade and spread
 High mitotic count

29. Squamous Cell Carcinoma
 Keratin Pearls

30. Disorders of Pigmentation

31. Vitiligo
 Autoimmune basis
 Hypopigmented/ white plaque
 pigment forming cells known as melanocytes
are injured

32. Vitiligo

33. Proliferative Melanocytic
Lesions
 Nevi
 Benign growths of young melanocytes.
 Many of them congenital.
 Dysplastic nevus
 Abnormal maturation.
 May become malignant
 Malignant melanoma

34. Dermal Nevus
 Clusters of young melanocytes.
 Confined to dermis.

35. Nevi

36. Dysplastic Nevus
 Abnormal maturation of nevus cells
 May proceed to malignant melanoma
 Sometimes part of a familial syndrome.

37. Malignant Melanoma
 Malignant melanocytic tumor
 Very unpredictable tumor
 Genetics
 Solar and UV exposure
 Ethnic
 Radial growth followed by
 Penetrating phase
 Metastasis

38. Malignant Melanoma
 Nodular or vertical
growth
 Depth >2 mm
 Bad development
 Sites
 Skin
 Conjunctiva
 Retina
 Iris
 Meninges

39. Dermal Tumors
 Fibroma

40. Xanthomas
 Histiocytes
containing lipid
 Around eyes
 Extensor surfaces
of extremities
 Diabetes
 Liver disease
 Hyperlipidemia

41. Blistering Conditions
 Pemphigus vulgaris
 Bullous pemphigoid
 Dermatitis herpetiformis

42. Cleft Position is Important
 Subcorneal: Impetigo
 Suprabasalar: Pemphigus vulgaris
 Subepidermal or basilar:
 Bullous pemphigoid
 Dermatitis herpatiformis

43. Pemphigus vulgaris
-

44. Bullous Pemphigoid
 Antibodies against hemidesmosomes.
 Hemidesomsomes anchor epidermis to
basement membrane

45. Skin Adnexal (Appendage) Tumour
 Eccrine poroma- sweat gland differentiation
 Cylindroma- Ductal (apocrine or eccrine differentiation)
 Syringoma- eccrine differentiation
 Sebaceous adenoma
 Pilomatricoma – hair follicular differentiation

46. Tumours of Cellular Migrants to
Skin
 Mycosis Fungoides (Cutaneous T-cell Lymphoma)

47. THANK YOU