Pathology of the Integumentary System - Part 1 Flashcards
Case example
* 11 y/o, FS, mixed breed dog
* 1 year history of skin disease.
* Lesions are pruritic. Patient has chronic
history of non-seasonal pruritus.
* Partial improvement with short courses of
prednisone and antibiotic.
* Crusting on the muzzle, nasal bridge, and
paw pad
Recognize and describe the
common gross cutaneous lesions.
What is the clinical history?
Is it pruritic?
Seasonal? Non-seasonal?
How does the patient respond to treatment?
Responsive to immunosuppressive treatment? Antimicrobial treatment?
- Cytology:
- Neutrophils with numerous acantholytic cells.
- No bacteria seen.
- Differential diagnosis:
- Pemphigus foliaceus (most likely), pyoderma
- Submit skin punch biopsies for a
definitive diagnosis
The skin acts as a protective barrier. Some of its functions are:
* Continuously sheds – ________
* Protect against ____ loss (hydrophobic), _______
agents, chemicals, and physical ____
* Photoprotection: pigmentation (_______) and hair
prevent ____ damage.
desquamation, fluid, microbiologic, injury, melanocytes, solar
Additional functions of skin:
Functions of skin
* _______ regulation
* _______ perception
* Storage of _____
* Absorptive surface
* ________-regulation
* ________ action
Temperature, Sensory, nutrients, Immuno, Antimicrobial
Immune cells are constantly surveying skin, antimicrobial peptides as well.
Describe how the skin produces vitamin D?
- Vitamin D maintains calcium phosphorus ratio
- Regulate epidermal differentiation and proliferation
The skin is usually an indicator of ?
General health and disease
What can be seen here?
Hair coat and skin health can be an indicator of general health.
Neoplasia, diseases affecting visceral organs, can manifest itself as skin disease.
How to describe lesion characteristics?
- Distribution: Anatomic location
- Focal, multifocal
- Any mucous membrane involvement (e.g. oral cavity)?
- Symmetric or Asymmetric
- Size
- Shape
- Configuration
- Type: Primary (underlying cause of disease) vs Secondary lesion (secondary to
?)
Make sure to point out whether lesion(s) is on haired or non-haired skin
What type of lesion distribution pattern can be seen here?
Bilaterally symmetric
What type of lesion distribution pattern can be seen here?
Asymmetric distribution pattern
Label the image accordingly
Primary lesion
* A lesion _______ associated with the _______ process.
* Examples: ?
* Choice for skin biopsy!
directly, disease, Macule or patch, papule or plaque, pustule, vesicle or bulla, wheal, nodule, cyst,
List examples of Primary or secondary lesions
- Examples: Alopecia, scale, crust, follicular casts, comedo, and pigmentary abnormalities
All Smart Cute Fairies Can Pick Cute Asses
Secondary lesion
* Modification of a _______ lesion that results from evolution of the _______ lesion, traumatic ______, or other _____ factors.
* Examples: Epidermal collarette, scar, excoriation, erosion or ulcer, fissure, lichenification,
callus
primary, primary, injury, , external,
Erythema
reddening of the skin
Hyperpigmentation:
increase in pigment
Hypopigmentation:
decrease in pigment
Macule
A flat circumscribed lesion of altered skin color; macule < 1 cm
Patch
A flat circumscribed lesion of altered skin color; patch > 1 cm
What type of lesion is pictured here?
Describe its shape, configuration, and size.
Give examples.
Macule
flat circumscribed lesion of altered skin color
Examples: Hemorrhage, lentigo, vitiligo
What type of lesion is pictured here?
Describe its shape, configuration, and size.
Give examples.
Patch > 1 cm
flat circumsized lesion of altered skin color
Can be erythematous, or hyperpigmented, or hypopogmented.
What type of lesion is pictured here?
Describe its shape, configuration, and size.
Give examples.
Papule
Solid elevated lesion; < 1 cm diameter. Inflammatory cells accumulated under the skin.
Examples of where you would see this: Allergic reaction, bacterial folliculitis, etc.
What type of lesion is pictured here?
Describe its shape, configuration, and size.
Give examples.
Flat elevation in skin; > 1 cm diameter.
Examples: Calcinosis cutis, eosinophilic plaque
Coyner, 201920
Primary lesion
Called an eosiniphyllic plaque.
What type of lesion is pictured here?
Describe its shape, configuration, and size.
Give examples.
Pustule; Circumscribed raised superficial accumulation of purulent
fluid within the epidermis.
Examples: bacterial infection, pemphigus foliaceous.
What type of lesion is pictured here? _______ circumscribed elevation of _____ filled with ____ fluid
Describe its shape, configuration, and size.
Give examples.
Vesicle and Bulla
Sharply, epidermis, clear; vesicle < 1 cm; bulla > 1 cm.
Examples: viruses, chemicals, burns and autoimmune diseases.
Primary lesion
What type of lesion is pictured here? _____ circumscribed raised lesion consisting of ____
Describe its shape, configuration, and size.
Give examples.
Wheal –> Sharply, edema
Examples: Insect bites, urticaria, allergic reaction
What type of lesion is pictured here?
Describe its shape, configuration, and size. Where does this lesion typically extend into?
Give examples.
Nodule –> Circumscribed solid elevation > 1 cm in diameter that
usually extends into deeper layers of skin
Examples: bacterial or fungal infection, neoplasm etc.
24
Primary lesion
What type of lesion is pictured here? What is this lesion lined with? What is it filled with, if anything?
Describe its shape, configuration, and size.
Give examples.
Epithelium-lined cavity containing fluid or a solid material. It is a
smooth, well-circumscribed, fluctuant to solid mass.
Examples: follicular cyst and apocrine gland cyst.
Miller et al, 201325
Primary lesion
What type of lesion is pictured here?
Describe its shape, configuration, and size.
Give examples.
Alopecia –> Partial to complete loss of hair
Examples: endocrine dermatopathy, follicular dysplasia (can not gorw normall)`
What type of lesion is pictured here? Sheets of ______ cells that split and ______ from underlying _____ as _____, thick or thin, dry or oily fragments, may adhere to hairs.
Describe its shape, configuration, and size.
Give examples.
Scale
cornified, separate, epidermis as
irregular
Examples: cornification disorders such as sebaceous adenitis and ichthyosis.
Primary or secondary lesion
What type of lesion is pictured here? ________ composed of ____ accumulations of ?
Describe its shape, configuration, and size.
Give examples.
Crust – desquamation, dry accumulations of serum, pus, and epithelial and
bacterial debris.
Examples: chronic stage of pustular disease (bacterial infection or pemphigus foliaceous).
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Primary or secondary lesion
What type of lesion is pictured here? Accumulation of _____ and ______ material that adheres
to ____ _____ extending above surface of ______ ____.
Describe its shape, configuration, and size.
Give examples.
Follicular cast
Accumulation of keratin and follicular material that adheres
to hair shaft extending above surface of follicular ostia.
Example: sebaceous adenitis
What type of lesion is pictured here?
Describe its shape, configuration, and size.
Give examples.
Follicular cast
Yellow is from keratian plugwhich plus tbe hir follcile
What type of lesion is pictured here?
Describe its shape, configuration, and size.
Give examples.
Comedo
Dilated hair follicle filled with cornified cells and sebaceous material
Examples: solar dermatosis (canine), chin acne and endocrine dermatopath
What type of lesion is pictured here?
Describe its shape, configuration, and size.
Give examples.
Abnormal pigmentation
Changes in skin coloration caused by a variety of pigments
Examples:
* Hypopigmentation – vitiligo
* Hyperpigmentation: postinflammatory, chronic, traumatic, and endocrine skin lesions
Miller et al, 201331
Primary or secondary lesion
What type of lesion is pictured here? A ____ layer of ___ that expands _______ and forms a ___.
Describe its shape, configuration, and size.
Give examples.
Epidermal collarette
A thin layer of scale that expands peripherally and forms a ring.
Examples: superficial bacterial infection (pyoderma), insect
bite, fungal infection.
What type of lesion is pictured here?
Describe its shape, configuration, and size.
Give examples.
Scar
Fibrous tissue that replaces normal skin after dermis injury and/or
laceration. On the skin, these areas are oft.
Bipsy is a wastge of tiem - do not send ofr pathology
Scar: Fibrous tissue that replaces normal skin after dermis injury and/or laceration.
On the skin, these areas are often alopecic and depigmented.
Examples: healed wound, surgical scar.
Do not send to pathologist -> it will give you no information.
What type of lesion is pictured here?
Describe its shape, configuration, and size.
Give examples.
Excoriation
Superficial, linear break of the epidermis.
Examples: mechanical trauma, the macerating action of secretions, and constant humidity.
What type of lesion is pictured here?
Describe its shape, configuration, and size.
Give examples.
Erosion
Partial-thickness loss of epidermis resulting in shallow, moist, glistening depression.
Examples: Secondary to vesicle or pustule rupture or secondary to surface trauma,
immune-mediated disease
What type of lesion is pictured here?
Describe its shape, configuration, and size.
Give examples.
Ulcer: Full-thickness loss of epidermis and basement membrane, and at least a portion of the dermis with depression of the exposed surface.
Examples: ischemic lesions resulting from vasculitis, indolent ulcer, feline herpesvirus dermatitis, feline ulcerative dermatosis syndrome.
What type of lesion is pictured here?
Describe its shape, configuration, and size.
Give examples.
Fisssure
A deep, linear break from epidermis into the dermis.
Examples: paw pad fissure seen in pemphigus foliaceus,
superficial necrolytic dermatitis, or digital hyperkeratosis
What type of lesion is pictured here?
Describe its shape, configuration, and size.
Give examples.
Linchenification Rough, thickened epidermis secondary to persistent rubbing,
scratching, or irritation; may have increases pigmentation.
Examples: chronic dermatitis.
Secondary lesion
What type of lesion is pictured here?
Describe its shape, configuration, and size.
Give examples.
Callus: Thick firm, hyperkeratotic, hairless plaque with increased skin folds, wrinkles or fissures.
Examples: trauma over bony prominence such as elbow, sternum, or side of digit
Secondary lesion
Diagosis ofr skin scrapogng (1)
Diagnostics – Skin scraping (2)
Diagnostics – Cytology & taping
Whenever you hae=ve a noduke, Aspiration.
Diagnostics – Microbial culture
* Superficial infections: Skin swab for
aerobic bacteria
Coyner, 201945
Diagnostics – Microbial culture
- Panniculitis, draining tracts or nodules:
- Tissue culture (sterile procedure) for aerobic and anaerobic bacteria,
Mycobacterium, and fungi - Use excisional biopsy or double-punch method
Diagnostics – Dermatophyte culture
- Technique: hair pluck, toothbrush technique
- Dermatophyte test medium (DTM)
- Dermatophyte PCR
Can culture dermatophyte after shine lught and brush
- Serology or intradermal testing
- Only performed when the clinical
diagnosis of atopic dermatitis has
been made by first ruling out all
other causes of pruritus/dermatitis
After clincial diagnosi of atopic dermatitis?
Diagnostics – Skin biopsy
* When?
- The disease that can only be diagnosed by a skin biopsy
- Failure to respond to rational therapy
- Severe clinical presentations
- Persistent ulcers, vesicles, and bullae
- Nodular or neoplastic lesions
- To guide clinical treatment
49
Acute
Erythema, papules, pustules
Chronic
Lichenification, hyperpigmentation
Diagnostics – Skin biopsy
1. Which lesions should you use for a skin biopsy?
2. How big should your biopsy sample be for most locations? What are the exceptions?
- Primary lesions
- Size: 6-8 mm for most location; 4 mm for paw, nasal planum, periocular region, or eyelid
Tips for skin biopsy
* Avoid ____-_______ therapy (e.g. steroid) for at least 2
weeks
* Treat ____ infections prior to biopsy
* Use cytology / scrapings / dermatophyte cultures to identify ______
infections
* Submit _____ _____ for nodular or draining tracts
* Culture for ?
* Don’t ____ the skin or soak in _____
* Include ____ and ____ in your sample
* Provide appropriate clinical history and list your clinical
differential diagnoses.
anti-inflammatory, secondary, secondary, tissue culture, aerobic, anaerobic bacteria, Mycobacterium, and fungi, scrub, antiseptics, crusts, scales
What can be seen here?
Skin punching biopsy
Additional testing
* ________ stains
* Gram: ____
* _______ _____ ____ (PAS): fungi
* Acid-fast: ______
* _______ ______ _____ (GMS): fungi, oomyces
*_________ stains
* Infectious agents
* ______ – epithelial, mesenchymal, round cell etc.
* ____________ (PCR)
* PCR for ? (PARR)
Histochemical, bacteria, Periodic acid–Schiff, mycobacterium, Grocott’s Methenamine Silver, Immunohistochemical, Neoplasia, Polymerase chain reaction, Antigen Receptor Rearrangements
