Dermatopathology Flashcards
What are the functions of skin?
- Enveloping barrier
- Protection from environment
- Motion and form
- Appendages
- Regulation of temperature
- Storage unit
- Indicator
- Immune regulation
- Pigmentation
- Defense against microorganisms
- Sensory function
- Secretion and excretion
- Metabolism (Vit. D3 synthesis)
- Blood pressure
What are the layers of the epidermis?
- Stratum corneum- keratinized cell layer
- Stratum lucidum- translucent cell layer
- Stratum granulosum- granular cell layer
- Stratum spinosum- prickle cell layer
- Stratum basale- basal cell layer
What are the cell types of the epidermis?
- Keratinocytes
- Melanocytes
- Langerhans cells
- Merkel cells
- Mast cells
What are intercellular adhesions between keratinocytes?
Desmosomes (“adherens junctions”)
What are adhesions from keratinocytes to the basement membrane?
- Hemidesmosomes
- Focal adhesions
What comprises the dermo-epidermal junction?
- Lamina lucida (bullous pemphigoid antigen, laminin, proteoglycan)
- Lamina densa (type IV collagen)
- Sub-lamina densa zone (type I, III, VII collagen)
What makes up the dermis?
- Collagen fibers
- Fibroblasts
- Dermal dendrocytes
- Melanocytes
- Mast cells
What makes up the subcutis/hypodermis/panniculus?
- Adipocytes
- Skeletal muscle cells
- Endotheliocytes
- Smooth muscle cells
- Nerves/ganglia
What makes up the adnexa of skin?
- Hair follicles
- Arrector pili muscles
- Sebaceous glands
- Apocrine sweat glands
- Eccrine sweat glands
What are the phases of the hair cycle?
- Telogen
- Eary anagen
- Anagen
- Anagen
- Early catagen
- Catagen
What are the blood and lymph plexuses of the skin?
- Superficial (subpapillary)
- Middle (mid-dermal)
- Deep (subcutaneous)
What are some challenges associated with skin diseases?
- Diverse problems with similar clinical presentation
- Conditions producing multiple patterns
- Stereotypical response of chronic skin conditions
- Pruritic conditions with secondary (self-inflicted) lesions
- Misunderstanding (representing) control for cure
- Frustrated owners
- Need for a bigger team (owner, practitioner, pathologist, microbiologist)
Describe this lesion.
Fluid-filled vesicle/cyst over the level of the surface of the skin
Describe this lesion.
Pustules, raised over the surface of the skin
Describe this lesion.
Solid, raised growth; papule (notice the hairs)
Describe this lesion.
Nodule; histiocytoma
Describe this lesion.
Hyperpigmentation within the level of the skin
Describe this lesion from a horse.
Indentation; ulcer
Describe this lesion.
Crust
Describe this lesion.
Dry; fissures
Describe this lesion.
Loss of hair, hyperpigmentation
Describe this lesion.
Sharp demarcation, hemorrhage, scab, ulcer
What is the difference between a primary lesion and a secondary lesion?
- Primary lesion- direct result of injury
- Secondary lesion- develop from primary lesions over time due to healing, traumatization, secondary infection, treatment…
This primary lesions is flat, has (dis) coloration, and is
Macule (color change within skin)
This primary skin lesion is like a macule, but > 1 cm.
Patch
This primary skin lesion is a solid elevation < 1 cm
Papule (epidermal, dermal)
This primary skin lesion is a round-topped solid elevation > 1 cm.
Nodule (superficial, deep)
This primary skin lesion is a flat-topped solid elevation > 1 cm.
Plaque (superficial, deep)
This primary skin lesion is an edematous elevation in the dermis.
Wheal
This primary skin lesions is a fluid-filled elevation
Vesicle
This primary skin lesion is a fluid-filled elevation > 1 cm.
Bulla
This primary skin lesion is a cell-filled elevation (cavity), usually with granulocytes.
Pustule
This is a multi-chambered pustule.
Pock
These are tightly clustered pustules.
Impetigo
This primary/secondary skin lesion is defined as hair loss.
Alopecia
- Thin hair coat
- Over 30% hair loss before clinical
- Primary: ex. follicle dysplasia like color dilution
- Secondary: ex. trauma
This primary/secondary skin lesion is defined as flakes of keratinized layer.
Scale (flake, squame)
- Primary: hyperkeratosis (seborrhea)
This primary/secondary skin lesion is defined as keratin cylinders extending from follicles.
Follicular cast
This primary/secondary skin lesion is defined as the plugging of hair follicles by keratin and sebum.
Comedone
- “Black heads”
- Ex. follicular hyperkeratosis (also epidermal hyperplasia)
This primary/secondary skin lesion is defined as too much or too little pigment.
Pigmentary disturbances (hypermelanosis, [hypo]leukoderma, [hypo]leukotrichia)
This secondary lesion is a ring of scales that progresses outward.
Epidermal collarette (“collar of crusts”)
This secondary lesion are dried consolidations/exudate on the skin (serum, cells…).
Crust
This secondary lesion is a loss of epidermis (basement membrane intact).
Erosion