Dermatopathology Flashcards
What is perivascular dermatitis?
A very common pattern but is least diagnostic. Includes hypersensitivity reactions, response to ectoparasites, bacterial infections.
Why take a skin biopsy?
Inflammatory skin disease - make a diagnosis, confirmation of diagnosis before starting therapy, rule out other conditions. neoplasia - Identify and confirm neoplasia, prognosis, monitor progression or effect of therapy.
What is interface dermatitis?
Lesions targets the upper level of dermis/dermo epidermal junction/lower level of epidermis. There is Hydropic degeneration and apoptosis of cells in the stratum basale. Interface dermatitis can be cell poor or cell rich. Includes drug eruptions, discoid and systemic lupus erythematosus.
What is vasculitis?
In contrast to perivascular dermatitis, here the reaction is targeted against the blood vessels themselves.
What is nodular and diffuse dermatitis?
Can be nodular or the nodules can coalesce resulting in the effacement of a normal dermal architecture. Examples include abscesses, cellulitis, mycobacterial infections, leishmaniasis, foreign body reactions, fungal infections, eosinophilic granuloma complex, vaccine reactions.
What is intraepidermal vesicular &/ pustular dermatitis?
In general these can form either by an extension of spongiosis, hydropic change, acantholysis or frictional cleavage. Neutrophil dominated - superficial bacterial infection, pemphigus foliaceous. Eosinophil dominated- parasitic disease, allergic reactions. Minimal inflammation - pemphigus vulgaris.
What is subepridermal vesicular and pustular dermatitis?
Rare- the top of the bulla/ veiscle comprises the entire epidermis - example = bullous pemphigoid.
What is sebaceous adenitis?
Sebaceous glands specifically targeted. In chronic cases, glands may be absent.
What is panniculitis?
Subcutaneous adipose tissue is involved in the Inflammatory reaction. Often in association with deep dermal inflammation. Most common type is Pyogranulomatous e.g associated with foreign body vaccine reactions, deep fungal infections etc.
What is atrophic Dermatosis?
Atrophy of hair follicles and adnexal structures. Can also affect the dermis and epidermis. Most important in this category are the endocrinopathies. Developmental disorders can also be associated with atrophic changes. hair cycle abnormalities: prolonged telogen phase of the cycle. Dysplasia: Defect in the formation of the hair shaft. Typical features associated with endocrinopathies include follicular atrophy, sebaceous gland atrophy, diffuse orthokeratotic hyperkeratosis, secondary bacterial infection.
Define acantholysis
Loss of cohesion between epidermal cells
What is acanthosis
Increased thickness of stratum spinosum specifically, i.e thickening of non cornified cells, often accompanied by rate peg formation.
What is furunculosis?
:penetrating or perforating folliculitis resulting in hair follicle rupture.
What is orthokeratotic hyperkeratosis?
Thickening of stratum corneum - thickened layer of keratin
What is the lichenoid band?
Band of inflammatory cells just below the epidermis.
