Dermatopathology Flashcards
1
Q
Acantholysis
A
Loss of keratin cohesiveness
2
Q
Acanthosis
A
Increased thickness of stratum spinosum
3
Q
Alopecia
A
Hair loss/ failure to grow
4
Q
Atopy
A
Allergic skin disease
5
Q
Ballooning degeneration
A
Intracellular oedema
6
Q
Bullae
A
Collection of fluid > 1cm in diameter
7
Q
Folliculitis
A
Luminal, mural or perifollicular inflammation of the hair follicle
8
Q
Furunculosis
A
Luminal, mural or perifollicular inflammation secondary to rupture of the follicular wall (keratin = non-self)
9
Q
Dermal pyogranulomatous inflammation
A
Furunculosis
10
Q
Hyperkeratosis
A
Increased keratin thickness (may be para/ orthrokeratotic nuclei)
11
Q
Parakeratotic
A
Nuclei seen
12
Q
Orthokeratotic
A
No nuclei seen
13
Q
Pustule
A
Cavitation of epidermis filled with inflammatory cells
14
Q
Pigmentary incontinence
A
Melanin/ melanophages within the dermis
15
Q
Seborrhoea
A
Increased scale with or without greasiness
16
Q
Seborrhoea olesa
A
Increased scale with increased greasiness
17
Q
Seborrhoea sicca
A
Increased scale without greasiness
18
Q
Spongiosis
A
Epidermal intercellular oedema
19
Q
Vesicle
A
Fluid filled blister
20
Q
Name three aetiological agent which cause vasculitis
A
Rickettsia
Autoimmunity - immune complexes
Erysipelothrix - septic emboli
21
Q
Purpura
A
Purple-red rash of the skin
22
Q
Vasculitis is characterised by what gross changes?
A
Erythema
Plaques
Macules
Purpura
Ulceration
Dermal atrophy with chronicity
23
Q
Describe this lesion
A
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
Q
What pathological change is seen on this histological slide?
A
Adnexal atrophy - fading follicles, characteristic of chronic vasculitis
25
What type of vasculitis is characterised in this image?
What aetiology would be expected?
Neutrophilic
Due to type 3 hypersensitivity or septicaemia
26
What type of vasculitis is characterised in this image?
What aetiology would be expected?
Lymphoplasmacytic
Cell-mediated
27
What type of vasculitis is characterised in this image?
What aetiology would be expected?
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.
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
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
Subcorneal pustular dermatitis
Epidermis covered with ortho- and parakeratotic hyperkeratosis
Neutrophils and bacterial colonies
Aetiology: Staphylococcus hyicus
32
Which pathogen is shown here?
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?
"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
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.
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
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
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
53
Which species cause dermatophytosis?
Microsporium
Trichophyton
Epidermophyton
54
Transmission of dermatophytosis.
Infected hair/ keratin fragments
55
Describe this lesion
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
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
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
Necrotic debris surrounded by inflammatory cells - eosinophils and epithelioid macrophages
Chronic focal severe eosinophilic necrotising dermatitis
Pythiosis and Lagenidiosis
62
Describe this lesion
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
65
Describe the immune response and therefore lesions caused by infections of Leishmaniasis.
1. TH1 - alopecic
2. TH2 - nodular
66
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
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
MF-C
Oedematous, firm plaques
Well demarcated
Urticaria - Type 1 hypersensitivity
71
Atopic dermatitis
Cause
IgE hypersecretion
72
Excoriation
Self-trauma related abrasion
73
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
Pemphigus foliaceus
Superficial epidermis affected
77
Pemphigus complex
Pemphigus vulgaris
Detachment at mucocutaneous junction
78
Pemphigus complex
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
82
Describe alopecia areata
Bulbal inflammation and fragmentation of hairs
## Footnote
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?
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:
## Footnote
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
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
Degenerate collagen surrounded by eosinophilic inflammatory cells - FLAME FIGURE
Eosinophilic granuloma
91
Severe eosinophilic infiltrates of the skin associated with indolent ulcer
92
Describe this lesion found on a horse.
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
Focal, well demarcated 2x2cm round lesion. Encalsulated friable material.
Subacute focal moderate keratinous dermal cyst
97
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)
99
Describe
Ulcerated exophitic mass.
Dermal neoplasia
Squamous cell carcinoma
100
Keratin pearls often associated with squamous cell carcinoma
101
Poor demarcation
Locally invasive
Anisocytosis, anisokaryosis
Multiple mitosis
102
Basal cell tumour
Small hyperchromic nuclei
High mitotic index
103
INFUNDIBULAR KERATINISING ACANTHOMA
Infundibular differentiation with keratohyalin granules in the granular layer
Central lumen filled with keratin surrounded by squamous epithelial cells and collagen
104
TRICHOLEMMOMA
Clear keratinocytes similar to the isthmic outer root sheath cells
Benign, originating from the external hair root sheath
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
106
Trichoepithelioma
Neoplastic proliferation of all three layers of the hair follicle
Multinodular cream masses
Hyperplasia of follicular epithelium, hyperkeratosis
107
Trichblastoma
Germ cell proliferation
108
Sebaceous gland adenoma - similar construction to sebaceous gland - vacuolated (fatty) cells with peripheral nucleus
109
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?
Highly organised, well-demarcated, little pleomorphism (well differentiated)
Adenoma
112
What type of hepatoid gland tumour is shown here?
Disorganised lobular pattern
Higher cellular atypia and mitotic index
Local invasion
113
What type of apocrine tumour is seen here?
Adenoma - well differentiated (non-encapsulated), little mitosis and pleomorphism
114
Fibroma - characterised by streams of well differentiated fibrocytes and collagen
115
Sarcoid - fibroblast tumour
Biphasic tumour: both an epidermal and a dermal component, although the connective tissue is the preponderant proliferating tissue
116
Streams of neoplastic cells, infiltration into muscular tissue. Lymphocytic inflammation.
Pleomorphic and mitotic cells
117
Myxoma
Tumour originating from primitive fibroblasts
Loosly arranged spindloid cells
118
Describe this lesion
Focal ulcerated red raised lesion, exudative
Cutaneous haemangiopericytomat - whorls of neoplastic cells surround vessels
119
Describe this lesion
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
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
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
Non-encapsulated, pleomorphic, highly mitotic cells with close association with eosinophils.
Plasmacytic differentiation may occur: Perinuclear halo, Russel bodies, Amyloid
125
Calcinosis cutis
Caused by hyperadrenocorticism
Widespread dermal mineralisation of collagen and basement membrane
126
Calcinosis circumscripta
Localised mineralisation of dermis
Dermal lakes and inflammation in acute and fibrosis and metaplasia of cartilage in chronic lesions
