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Flashcards in Dermatopathology Deck (126):
1

Acantholysis

Loss of keratin cohesiveness

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2

Acanthosis

Increased thickness of stratum spinosum

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3

Alopecia

Hair loss/ failure to grow

4

Atopy

Allergic skin disease

5

Ballooning degeneration

Intracellular oedema

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6

Bullae

Collection of fluid > 1cm in diameter

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7

Folliculitis

Luminal, mural or perifollicular inflammation of the hair follicle

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8

Furunculosis

Luminal, mural or perifollicular inflammation secondary to rupture of the follicular wall (keratin = non-self)

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9

Dermal pyogranulomatous inflammation

Furunculosis

10

Hyperkeratosis

Increased keratin thickness (may be para/ orthrokeratotic nuclei)

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11

Parakeratotic

Nuclei seen

12

Orthokeratotic

No nuclei seen

13

Pustule

Cavitation of epidermis filled with inflammatory cells

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14

Pigmentary incontinence

Melanin/ melanophages within the dermis

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15

Seborrhoea

Increased scale with or without greasiness

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16

Seborrhoea olesa

Increased scale with increased greasiness

17

Seborrhoea sicca

Increased scale without greasiness

18

Spongiosis

Epidermal intercellular oedema

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19

Vesicle

Fluid filled blister

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20

Name three aetiological agent which cause vasculitis

Rickettsia

Autoimmunity - immune complexes

Erysipelothrix - septic emboli

21

Purpura

Purple-red rash of the skin

22

Vasculitis is characterised by what gross changes?

Erythema

Plaques

Macules

Purpura

Ulceration

Dermal atrophy with chronicity

23

Describe this lesion

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The skin of this pig shows multifocal to coelescing 'diamond-shaped' erythrematous red lesions. They range in size from 3x3 cm to 1x1cm. They are dark red at the periphery but often have a pale centre.

Acute severe multifocal-coelescing erythrematous vasculitis

Diamond disease - Erysipelothrix

24

What pathological change is seen on this histological slide?

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Adnexal atrophy - fading follicles, characteristic of chronic vasculitis

25

What type of vasculitis is characterised in this image?

What aetiology would be expected?

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Neutrophilic 

Due to type 3 hypersensitivity or septicaemia

26

What type of vasculitis is characterised in this image?

What aetiology would be expected?

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Lymphoplasmacytic

Cell-mediated

27

What type of vasculitis is characterised in this image?

What aetiology would be expected?

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Eosinophilic

Type 1 hypersensitivity

28

What histological changes would be expected with vasculitis?

Karyorrhectic cell debris

Fibrinoid necrosis + fibrin/ haemorrhage

Faded follicles with chronicity

29

Describe the lesion.

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Multifocal to coelescing redenning of the skin. Round lesions show flaking scale at the edges and range from 1x1cm to 3x3cm. Erythrematous papules.

Histologically: subcorneal pustules and n# infiltration

Acute moderate to severe multifocal to coelescing haemorrhagic dermatitis

Aetiology: Pemphigus foliaceus

30

Describe this lesion

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The skin of this piglet shows extensive focal erythema. Large grey to brown crusts are present. Approximately 20% of the skin of the face is affected.

Acute severe focally extensive bacterial dermatitis.

Aetiology: Staphylococcus hyicus exotoxin (MMP)

31

Describe the lesion

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Subcorneal pustular dermatitis 

Epidermis covered with ortho- and parakeratotic hyperkeratosis

Neutrophils and bacterial colonies

Aetiology: Staphylococcus hyicus

32

Which pathogen is shown here?

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Dermatophilus congolensis

33

Thick, parakeratotic crusts found on the head, back and hindquarters (ie persistently soaked) areas of a horse would be indicative of what pathogen?

Dermatophilus congolensis

34

Which species of bacteria are implicated in deep pyoderma?

Staphylococcus

Streptococcus

Corynebacterium

Pseudomonas

35

How would deep pyoderma lesions progress with increased pathology?

  1. Follicular papules
  2. Pustule
  3. Crust formation and coalescing ulcers and alopecia
  4. Dark red nodules, ulcers and fistulae
  5. Lymphadenopathy and fever
  6. Epidermal acanthosis

36

Abscess

Focal non-specific severe suppurative inflammation of the deep dermis and panniculum

37

Describe the histological appearance of an abscess.

Central core of neutrophilic debris and necrotic material surrounded by granulation tissue.

Well demarcated

38

Describe the histological appearance of cellulitis.

Poorly demarcated

Extensive suppurative/ pyogranulomatous inflammation

Oedema

Haemorrhage

Thrombosis

39

What histological changes are seen here?

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"Sulphur granules” - 
masses of basophilic to amphophilic organisms bordered by bright eosinophilic Splendore-Hoeppli material

Caused by Actinomyces/ Nocardia

40

Panniculitis

Inflammation of adipose tissue

41

Epitheliotrophic viruses.

Name four.

What histological changes are seen?

Pox viruses

  • Capri - sheep pox
  • Parapox - orf
  • Orthopox - cowpox
  • Suipox - swine pox

Histo: Cytoplasmic inclusion bodies

42

Describe the lesion

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Multifocal-coelescing crusting lesions. Peripheral erythema of lesions. Papules and pustules. Ulceration of lesions is seen.

Intracytoplasmic inclusion bodies on histology

Cowpox - particularly in immunosupressive lesions

43

Multifocal-coelescing raised to flat-grey crusts seen at the lip commissure of a lamb.

What aetiology would be expected?

Orf - parapox virus

44

Contagious pustular dermatitis

Orf

45

Multifocal to coelescing nodular oval masses over the ear pinnae.

Suggest an aetiological agent. 

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Swinpox

46

Aetiology of dermatophytosis

Microsporium

Trichophyton

Epidermophyton

47

Which of these statements is incorrect?

  1. In impetigo (superficial pyoderma) the prototype lesion is a neutrophilic pustule
  2. “Greasy pig” disease is caused by a poxvirus
  3. Herpes virus and poxvirus can cause a dermatopathological disease in cats
  4. In deep pyoderma the initial lesion is a suppurative folliculitis
  5. Orf virus is causing proliferative lesions at the lip commissures

2

48

What species of Malassezia is usually implicated in malassezia dermatitis?

Pachydermatis (commensal)

49

Which of these two species of fungi cause pruritic skin disease?

Malassezia or Trichophyton

Malassezia

50

Describe this lesion

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Chest and legs of the dog are focally extensively affected. There is severe lichenification of the skin with multifocal areas of erthema. The affected area shows severe alopecia and hyperpigmentation.

Chronic focally extensive severe dermatitis

Malassezia

51

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Peanut shaped malassezia fungi

52

What histological changes are present in Malassezia dermatitis?

  • Parakeratotic hyperkeratosis, epidermal hyperplasia with spongiosis. Mixed cell exocytosis occurs
  • Yeasts aggregate within crusts or the stratum corneum

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53

Which species cause dermatophytosis?

Microsporium

Trichophyton

Epidermophyton

54

Transmission of dermatophytosis.

Infected hair/ keratin fragments

55

Describe this lesion

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Multifocal to coelescing, raised, alopecic areas of skin. The peripheral area of each round lesion (2x2cm) shows mild crusting. Lesions apear firm to touch.

Chronic MF-C moderate granulomatous dermatitis

Dermatophytosis

56

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Fungal hyphae surround the hair follicle.

Dermatophytosis

57

Kerion

Mycotic pyogranuloma

58

Mycetoma

Which species is commonly involved?

Tumour-like lesion caused by fungi (due to wound contamination)

Actinomyces spp.

59

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Fungal hyphae surrounded by lymphocytes and plasma cells.

Extensive fibrosis

Eumycotic mycetoma - Actinomyces

60

Pythiosis and lagenidiosis is caused by what fungal species present in stagnant water?

Pythium insidiosum and Lagenidium

61

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Necrotic debris surrounded by inflammatory cells - eosinophils and epithelioid macrophages

Chronic focal severe eosinophilic necrotising dermatitis

Pythiosis and Lagenidiosis

62

Describe this lesion

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Focal raised ulcerated nodule (4x4cm)

Exposed subcut tissue is reddened and haemorrhagic fluid oozes from a deep tract.

Chronic focal severe haemorrhagic dermatitis

Pythiosis

 

63

Describe the two aspects of Zygomycosis.

  • Mucorales (angioinvasion and dissemination)
  • Entomophthorales (local subcutaneous granulomas)

64

Outline the lifecycle of Benoitosis protozoa and describe the lesions they cause.

  1. Lifecycle  - 2 host cycle - cat is definitive host
  2. Lesions - Intracellular cyst

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65

Describe the immune response and therefore lesions caused by infections of Leishmaniasis.

  1. TH1 - alopecic
  2. TH2 - nodular

66

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Amastigotes found within macrophages in blood sample - Leishmaniasis

67

Which parasitic species are associated with Myiasis?

  1. Cuterebra spp.: rabbit, rodents and, aberrantly, cats

  2. Hypoderma bovis and H. Lineatum : cattle (warble)

  3. Blowflies (lucilia, calliphora, etc): sheep

     

68

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Folliculitis, keratolysis, degenerative neutrophils

Chronic focal moderate suppurative necrotising dermatitis/ folliculitis

Demodecosis

69

Bruise

Locat subcut/ intradermal haemorrhage

Progression leads erythrophagocytosis and degradation of haem pigment and therefore the colour change

70

Describe this lesion

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MF-C

Oedematous, firm plaques

Well demarcated

Urticaria - Type 1 hypersensitivity

 

71

Atopic dermatitis

Cause

IgE hypersecretion

72

Excoriation

Self-trauma related abrasion

73

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Eosinophil infiltration of skin - autoimmune reaction

74

Insect hypersensitivity is what type of reaction

T1/ T4 hypersensitivity caused by insect saliva, venom etc

75

Name the three aspects of the pemphigus autoimmunity complex

Condition, autoimmunity against..

  1. Pemphigous folliaceous - desmoglein1
  2. Pemphigous vulgaris - desmoglein 3
  3. Bullous pemphigoid - BPAG1/2

 

76

Pemphigus complex

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Pemphigus foliaceus

Superficial epidermis affected

77

Pemphigus complex

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Pemphigus vulgaris

Detachment at mucocutaneous junction

78

Pemphigus complex

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Bullous pemphigoid

Cutaneous and mucosal detachment

79

What is the difference between Discoid and Systemic Lupus Erythematosus

Systemic -Involvement of multiple organs +/- skin lesions 

Discoid - Localized cutaneous form

80

Photosensitive dermatitis restricted to the nasal planum is indicative of what autoimmune condition?

Discoid lupus erythematosus

81

Describe erythema multiforme

•Type III and IV hypersensitivity reactions -deposition of immune-complexes in vasculature and basal membrane

•Two forms:

Minor - symmetrical bilateral erythematous papules and macules. Classical “target” lesions

Major - widespread mucosal lesions, extensive necrotising and vesiculobullous skin lesions and systemic illness

•Histo: Characteristic interface dermatitis with necrotic keratinocytes and satellitosis. Epidermal necrosis

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82

Describe alopecia areata

Bulbal inflammation and fragmentation of hairs

Histo: Peribulbar lymphocytic folliculitis - pigmentary incontinence - chronic lesions: telogen and atrophic follicles. Active inflammatory changes are difficult to observe

83

Deficiencies in vitamin a cause what clinical presentation?

Squamous epithelial hyperkeratosis (follicular keratosis)

84

Deficiency in vitamin e cause what clinical presentation?

Panniculitis due to steatonecrosis (lack of antioxidant protection)

 

85

Deficiency in vitamin b causes what clinical presentation

Dry seborrhoea with alopecia

86

You are presented with a pig with bilateral and symmetrical papules, erythema and crusts.

Discuss

Zinc deficiency

Histo - acathosis, epithelial hyperkeratosis (parakeratotic)

87

Superficial necrolytic dermatitis is characteristed by "french flag" histology.

What pathological changes lead to this?

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  1. Parakeratotic hyperkeratosis (red),
  2. Spongiosis and oedematous spinous layer (white)
  3. Basal layer hyperplasia (blue)

Unknown aetiology but associated with hormonal imbalances.

Grossly appears as erosions and erythema

88

You are presented with a dog with symptoms as follows:

Bilateral and symmetrical hypotrichosis and alopecia of trunk, abdomen. Skin is diffusely thinned and less elastic.  Hyperpigmentation, comedones and calcinosis cutis are also observed.

What would you suspect to find on histology?

Possible diagnosis?

Diffuse cutaneous atrophy with orthokeratotic hyperkeratosis and follicular keratosis

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89

Describe the difference between eosinophilic lesions in cats.

  • Eosinophilic plaque:
    • Highly pruritic
    • Inguinal, axillary and lateral thigh areas
  • Eosinophilic granuloma:
    • Raised, pink variably pruritic nodular lesions
    • Haired skin (linear) and oral mucosa (nodular)
  • •Indolent ulcer:
    • Ulcerated plaque-like lesion on the upper lip
    • Non pruritic and non painful

90

Describe

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Degenerate collagen surrounded by eosinophilic inflammatory cells - FLAME FIGURE 

Eosinophilic granuloma

91

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Severe eosinophilic infiltrates of the skin associated with indolent ulcer

92

Describe this lesion found on a horse.

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Severe collagen degeneration associated with collagenolytic granuloma

93

Where on the horse would you find eosinophilic lesions?

Axialla

Lateral trunk

(collagenolytic are spread about)

94

Epithelial tumours

Keratinocyte derived

95

Cutaneous adnexal tumours

Keratinocytes of follicles and glandular tissue

96

Describe this lesion

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Focal, well demarcated 2x2cm round lesion. Encalsulated friable material.

Subacute focal moderate keratinous dermal cyst

97

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Exophytic

Hyperkeratotic, hyperplastic epithelial growth

Dermal stalks support 

Papilloma - caused by papillomavirus

98

Koilocytes

keratinocytes with eccentric pyknotic nucleus and peripheral clear halo (ballooning degeneration)

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99

Describe

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Ulcerated exophitic mass.

Dermal neoplasia

Squamous cell carcinoma

100

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Keratin pearls often associated with squamous cell carcinoma

101

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Poor demarcation

Locally invasive 

Anisocytosis, anisokaryosis

Multiple mitosis 

102

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Basal cell tumour

Small hyperchromic nuclei

High mitotic index

103

INFUNDIBULAR KERATINISING ACANTHOMA

 

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Infundibular differentiation with keratohyalin granules in the granular layer

Central lumen filled with keratin surrounded by squamous epithelial cells and collagen

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104

TRICHOLEMMOMA

Clear keratinocytes similar to the isthmic outer root sheath cells

Benign, originating from the external hair root sheath

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105

PILOMATRICOMA

Derrived from follicular matrix cells

Appear chalky white on cut surface

Benign

Signs of matrical differentiation as seen in the hair bulb

Ghost cells - eosinophilic anuclear cells

 

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106

Trichoepithelioma

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Neoplastic proliferation of all three layers of the hair follicle

Multinodular cream masses

Hyperplasia of follicular epithelium, hyperkeratosis

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107

Trichblastoma

Germ cell proliferation

108

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Sebaceous gland adenoma - similar construction to sebaceous gland - vacuolated (fatty) cells with peripheral nucleus 

109

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Sebaceous epithelioma

Few sebocytes - lots of basal cells

110

A common perianal tumour found in dogs

Perianal adenoma - modified sebaceous gland neoplasia

111

What type of hepatoid gland tumour is shown here?

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Highly organised, well-demarcated, little pleomorphism (well differentiated)

Adenoma

112

What type of hepatoid gland tumour is shown here?

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Disorganised lobular pattern

Higher cellular atypia and mitotic index

Local invasion

113

What type of apocrine tumour is seen here?

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Adenoma - well differentiated (non-encapsulated), little mitosis and pleomorphism

114

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Fibroma - characterised by streams of well differentiated fibrocytes and collagen

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115

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Sarcoid - fibroblast tumour

Biphasic tumour: both an epidermal and a dermal component, although the connective tissue is the preponderant proliferating tissue

116

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Streams of neoplastic cells, infiltration into muscular tissue. Lymphocytic inflammation.

Pleomorphic and mitotic cells

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117

Myxoma

Tumour originating from primitive fibroblasts

Loosly arranged spindloid cells

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118

Describe this lesion

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Focal ulcerated red raised lesion, exudative 

Cutaneous haemangiopericytomat - whorls of neoplastic cells surround vessels

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119

Describe this lesion

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Non-encapsulated, well-circumscribed dermal or subcutaneous nodule formed by the confluence of dilated blood-filled channels lined by flattened endothelium.

Dermal haemangioma

120

Describe the lesions seen in this slide

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Anisocytosis

Anisokaryosis

Pleomorphic cells

Mitosis 

Aberent vascular channels

Haemangiosarcoma

121

Describe the histological changes associated with lipoma

Resembles normal adipose tissue

Infiltrative lipomas also resemble normal tissue but infiltrate between muscle fibres - rare

122

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Pleomorphic vacuolated fatty cells

Liposarcoma

123

Histiocytoma

Derived from langerhanns cells - dentritic immunological cells 

Often single domed mass which regress with lymphocyte infiltration

124

Describe this lesion

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Non-encapsulated, pleomorphic, highly mitotic cells with close association with eosinophils.

Plasmacytic differentiation may occur: Perinuclear halo,  Russel bodies, Amyloid

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125

Calcinosis cutis

Caused by hyperadrenocorticism

Widespread dermal mineralisation of collagen and basement membrane

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126

Calcinosis circumscripta

Localised mineralisation of dermis

Dermal lakes and inflammation in acute and fibrosis and metaplasia of cartilage in chronic lesions

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