Interpretation of Biopsies Flashcards
Patterns in responses to injury
- Perivascular dermatitis
- Interface dermatitis
- Vasculitis
- Nodular and/or diffuse dermatitis
- Vesicular/pustular dermatitis
○ Intraepidermal
○ Subepidermal - Folliculitis/furunculosis/adenitis
- Panniculitis
- Atrophic dermatosis
What is perivascular dermatitis?
Skin inflammation around blood vessels
* Leukocytes around vessels
* Oedema of dermis
The most common change seen - least specific
Not diagnostically useful
When is perivascular dermatitis seen?
FAD
Canine atopy
Pyoderma
Classification of perivascular dermatitis
Superficial
Mid-dermal/pericfollicular
Deep dermal
Cellular infiltrate of perivascular dermatitis?
Neutrophils
Lymphocytes
Eosinophils (Type I hypersensitivity)
What is interface dermatitis?
Inflammation of interface between epidermis and dermis
More specific than perivascular dermatitis
Pigment incontinence
+/- apoptosis
Associated with immune-mediate disease
What is vasculitis?
Inflammation of blood vessels
May cause microhaemorrhages
Variety of cell types included
Might also see:
* Panniculitis
* Dermal necrosis
* Atrophy of hair follicles
When do you see vasculitis
Primary or secondary reaction to:
Inflammation
Infection
Drug reactions
Neoplasia
Vaccination
What is nodular diffuse dermatitis?
Convergence of nodules to form diffuse pattern
Common in the dog
Cell types vary
Cell types seen in nodular diffuse dermatitis
Neutrophils
Pyogenic agents
Macrophages (granulomatous inflammation)
E.g. foreign bodies, mycobacteria
Neutrophils and macrophages (pyogranulomatous inflammation)
E.g. fungi
Eosinophilic
Parasitic?
Lymphocytic
Insect bites
Vaccine reactions
What is intraepidermal Vesicular/pustular dermatitis?
Clefting in epidermis leading to vesicles or pustules
Causes of intraepidermal Vesicular/pustular dermatitis
Epidermal inflammation/spongiosis
Intercellular oedema in epidermis
Desmosomes remain intact
Seen in:
□ Parasites
□ Infection
Acantholysis
Loss of cohesion between cells of the living epidermis
Desmosomes destroyed
Seen in:
□ Infection
□ Autoimmune disease (pemphigus)
Intracellular oedema
Mechanical forces
Classification of intraepidermal Vesicular/pustular dermatitis by position
Subcorneal - v superficial
□ Pemphigus foliaceus
□ Pyoderma
Suprabasilar - deeper
□ Pemphigus vulgaris
In follicular external root sheath
□ Pemphigus foliaceus
Classification of intraepidermal Vesicular/pustular dermatitis by cell type
Neutrophilic
□ Bacterial pyoderma
□ Pemphigus foliaceus
Eosinophils
□ Pemphigus foliaceus
□ Parasites
Subepidermal Vesicular/pustular dermatitis
Rare
Autoimmune
Severe dermal oedema
Severe interface dermatitis
