Dermatopathology Flashcards
Acantholysis
Loss of keratin cohesiveness
Acanthosis
Increased thickness of stratum spinosum
Alopecia
Hair loss/ failure to grow
Atopy
Allergic skin disease
Ballooning degeneration
Intracellular oedema
Bullae
Collection of fluid > 1cm in diameter
Folliculitis
Luminal, mural or perifollicular inflammation of the hair follicle
Furunculosis
Luminal, mural or perifollicular inflammation secondary to rupture of the follicular wall (keratin = non-self)
Dermal pyogranulomatous inflammation
Furunculosis
Hyperkeratosis
Increased keratin thickness (may be para/ orthrokeratotic nuclei)
Parakeratotic
Nuclei seen
Orthokeratotic
No nuclei seen
Pustule
Cavitation of epidermis filled with inflammatory cells
Pigmentary incontinence
Melanin/ melanophages within the dermis
Seborrhoea
Increased scale with or without greasiness
Seborrhoea olesa
Increased scale with increased greasiness
Seborrhoea sicca
Increased scale without greasiness
Spongiosis
Epidermal intercellular oedema
Vesicle
Fluid filled blister
Name three aetiological agent which cause vasculitis
Rickettsia
Autoimmunity - immune complexes
Erysipelothrix - septic emboli
Purpura
Purple-red rash of the skin
Vasculitis is characterised by what gross changes?
Erythema
Plaques
Macules
Purpura
Ulceration
Dermal atrophy with chronicity
Describe this lesion
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
What pathological change is seen on this histological slide?
Adnexal atrophy - fading follicles, characteristic of chronic vasculitis
What type of vasculitis is characterised in this image?
What aetiology would be expected?
Neutrophilic
Due to type 3 hypersensitivity or septicaemia
What type of vasculitis is characterised in this image?
What aetiology would be expected?
Lymphoplasmacytic
Cell-mediated
What type of vasculitis is characterised in this image?
What aetiology would be expected?
Eosinophilic
Type 1 hypersensitivity
What histological changes would be expected with vasculitis?
Karyorrhectic cell debris
Fibrinoid necrosis + fibrin/ haemorrhage
Faded follicles with chronicity
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
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)
Describe the lesion
Subcorneal pustular dermatitis
Epidermis covered with ortho- and parakeratotic hyperkeratosis
Neutrophils and bacterial colonies
Aetiology: Staphylococcus hyicus
Which pathogen is shown here?
Dermatophilus congolensis
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
Which species of bacteria are implicated in deep pyoderma?
Staphylococcus
Streptococcus
Corynebacterium
Pseudomonas
How would deep pyoderma lesions progress with increased pathology?
- Follicular papules
- Pustule
- Crust formation and coalescing ulcers and alopecia
- Dark red nodules, ulcers and fistulae
- Lymphadenopathy and fever
- Epidermal acanthosis
Abscess
Focal non-specific severe suppurative inflammation of the deep dermis and panniculum
Describe the histological appearance of an abscess.
Central core of neutrophilic debris and necrotic material surrounded by granulation tissue.
Well demarcated
Describe the histological appearance of cellulitis.
Poorly demarcated
Extensive suppurative/ pyogranulomatous inflammation
Oedema
Haemorrhage
Thrombosis
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
Panniculitis
Inflammation of adipose tissue
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
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
Multifocal-coelescing raised to flat-grey crusts seen at the lip commissure of a lamb.
What aetiology would be expected?
Orf - parapox virus
Contagious pustular dermatitis
Orf
Multifocal to coelescing nodular oval masses over the ear pinnae.
Suggest an aetiological agent.
Swinpox
Aetiology of dermatophytosis
Microsporium
Trichophyton
Epidermophyton
Which of these statements is incorrect?
- In impetigo (superficial pyoderma) the prototype lesion is a neutrophilic pustule
- “Greasy pig” disease is caused by a poxvirus
- Herpes virus and poxvirus can cause a dermatopathological disease in cats
- In deep pyoderma the initial lesion is a suppurative folliculitis
- Orf virus is causing proliferative lesions at the lip commissures
2
What species of Malassezia is usually implicated in malassezia dermatitis?
Pachydermatis (commensal)
Which of these two species of fungi cause pruritic skin disease?
Malassezia or Trichophyton
Malassezia
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