Pathology of Integument Pt 2 Flashcards
What are the components of the skin?
What are the layers seen in histology of the skin?
What are the components of the epidermis?
What are the functions of the keratinocytes?
What are the components of structural support of the skin?
What is hyperkeratosis? What is the cause (primary and secondary)? What are some examples?
Abnormalities of cornification: Hyperkeratosis
• Excessive thickening or hyperplasia of the stratum corneum.
• Cause
• Primary - Mutation (lipid, enzyme, structural protein)
• Example: ichthyosis • Secondary - Chronic irritation
• Example: Allergic skin disease, endocrine disorders, parasitic and bacterial infections.
What is occurring in this image?
Hyperkeratosis, Orthokeratosis ( the keratinocytes undergo complete cornification and loose their nucleus.
What is Orthokeratosis?
Orthokeratosis: the keratinocytes undergo complete cornification and thus lose their nucleus.
What is parakeratosis?
Parakeratosis: keratinocytes undergo only partial or incomplete cornification and thus retain their nucleus.
What can be seen in this image?
Parakeratosis ( Hyperkeratosis)
What is golden retriever ichthyosis?
Ichthyosis: Congenital and/or hereditary defects in the formation of the stratum corneum
• Strong breed predilection; genetic testing for ICH-1 (PNPLA1) or ICH-2
Where are the lesions generally located for golden retriever ichthyosis?
• Trunk
• Generalized scaling
• Lamellar orthokeratotic hyperkeratosis
What is seen in this image?
What is primary seborrhea? What is it controversial?
• Used to describe excessive scaling
• NOT a diagnosis
• Need to rule out other causes of scaling (e.g. ectoparasitism, metabolic diseases and endocrinopathies, allergic disease, etc.)
• Likely represents a variety of conditions such as pyoderma,
Malassezia dermatitis, sebaceous adenitis, allergic dermatitis,
Vitamin A-responsive dermatosis
What is epidermal hyperplasia? When may this occur?
• Epidermal hyperplasia (= acanthosis)
• Thickening due to increased number of
cells within the epidermis, especially of the stratum spinosum.
• A common response to chronic irritation
such as inflammation, trauma, metabolic or nutritional disorders
• Example: acral lick dermatitis
What is occurring in this image?
Epidermal Hyperplasia
What is acral lick dermatitis?
- Acral lick granuloma
• Dog
• A multifactorial disorder often associated
with underlying diseases such as atopy,
food allergy, trauma, endocrinopathy, bone
pain, neuropathy, or behavioral causes
• Consequences of chronic focal trauma +/-
secondary deep pyoderma.
• Dorsal carpus, or dorsolateral metatarsus.
• Focal alopecic, firm, raised plaque or
nodule
What is seen in this image?
Acral lick dermatitis/ granuloma
What is seen in this image?
Dermal lick granuloma/ dermatitis
What is apoptosis? What is necrosis?
• Apoptosis:
• Programmed cell death
• Cause: physiologic process, immune-
mediated disease
• Example: erythema multiforme
• Necrosis
• Death of cells and is characterized by
nuclear pyknosis, karyorrhexis, or karyolysis
• Cause: physical injury, chemical injury, ischemia
• Example: Photosensitization
What is seen here ?
Intercellular edema -> spongiosis
What is occurring here? What are examples?
Ballooning degeneration: superficial layer;
Example: viral infections
• Hydropic degeneration: basal layer;
Example: cutaneous lupus erythematosus
What is epidermal atrophy? What causes it?
What is occurring in this image?
Epidermal atrophy
What is acantholysis?
• Acantholysis: The disruption of intercellular junctions
(desmosomes) between keratinocytes of the epidermis
• Example: pemphigus foliaceus, pemphigus vulgaris
What is seen in this image?
Acantholysis
What other signs can you see of acantholysis?
What are inflammatory lesions of the epidermis ?
What are langerhans cells?
What is seen in this image?
Langerhans cells.
What is contact hypersensitivity also called?
Allergic contact dermatitis.
What hypersensitivity reaction is contact hypersensitivity?
• Hapten-type delayed hypersensitivity
(type IV hypersensitivity)
- test acting in same manner -> Tuberculin test.