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128 Cards in this Set
- Front
- Back
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General considerations of Integument pathology
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1. dermatopathology bridges clinical medicine & pathology
2. skin is largest organ in body & is in direct contact with external/internal evironments making it very susceptible 3. importance in veterinary practice (esthetic/ food animal) |
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In food animals certain cutaneous parasites cause:
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blemishes, decrease in production (meat, wool, milk), predispose to secondary infections, annoy animals, cause paralysis, unthriftiness, downgrading at market, and death
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epidermis layers
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basale
spinosum granulosum lucidum corneum disjunctum (depending on sites) |
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Epidermis cells
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keratinocytes
melanocytes Langerhans cells (Antigen-presenting cells) Merkel cells (neuroendocrine) |
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Epidermis - Adnexa:
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hair
glands sebaceous sweat (apocrine, epitrichial/eccrine, or atrichial) |
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General considerations of Integument pathology
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1. dermatopathology bridges clinical medicine & pathology
2. skin is largest organ in body & is in direct contact with external/internal evironments making it very susceptible 3. importance in veterinary practice (esthetic/ food animal) |
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In food animals certain cutaneous parasites cause:
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blemishes, decrease in production (meat, wool, milk), predispose to secondary infections, annoy animals, cause paralysis, unthriftiness, downgrading at market, and death
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epidermis layers
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basale
spinosum granulosum lucidum corneum disjunctum (depending on sites) |
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Epidermis cells
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keratinocytes
melanocytes Langerhans cells (Antigen-presenting cells) Merkel cells (neuroendocrine) |
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Epidermis - Adnexa:
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hair
glands sebaceous sweat (apocrine, epitrichial/eccrine, or atrichial) specialized glands (circumanal, tail, anal) claws hooves |
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epidermis- hepatoid
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perianal glands occur most commonly near the anus, but are also present in skin near the prepuce, tail, flank and groin
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Dermis- fibers
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collagen, reticulin, elastin
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Dermis- ground substance
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glycosaminoglycans, proteolycans
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Dermis- hair follicles
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anagen, catagen, telogen
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Dermis- cells
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fibroblasts, mast cells, histiocytes, smooth muscle
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Dermis - vessels
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blood, lymph
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Dermis- nerves
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motor & sensory fibers
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Hypodermis (cubcutis, panniculus) - lipocytes
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panniculus adiposes, digital cushion
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Hypodermis - fibers
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collagen, elastin
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Hypodermis- vessels
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blood (deep, middle, and superficial plexus), lymph
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Hypodermis- nerves
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Nerves
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Different anatomic sites - haired skin
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thin epidermis of haired skin has 1-3 layers of nucleated cells, a single, often discontinuous, stratum granulosum, and no rete ridges. There are however, regional variations in epidermal and dermal thicknes: the skin is thicker on the back and neck then on the abdomen & thickest in inguinal and axillary areas
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different anatomic sites - scrotal skin
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thicker epidermis than haired & often prominent epidermal pigmentation
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Different anatomic sites - footpads
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very thick epidermis with a multilayered spinosum, a two or three cell thick stratum granulosum and a wide compact stratum corneum
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different anatomic sites - nasal planum
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thick epidermis with a laminated stratum corneum and abscence of hair follicles and associated glands
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Functions of skin
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enclosing barrier
protection sensory temperature regulation shock absorption storage adnexia production secretion/excretion blood pressure control pigmentation immunoregulation/antibacterial action indicator or internal/systemic disease Sk |
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Skin- clinical expression of Dz
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alopecia
seborrhea pain & swelling tumor masses +/- ulceration vesicles Nodules hyperemia & congestion scabs & crusts puritis wheals, papules, macules, pustules, furuncles roughened thick epidermis melanosis or abscence of normal pigmentation |
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Skin- diagnosis of procedures
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history
physical examination laboratory examination of skin scrapings, culture, and biopsies other ancillary tests |
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Biopsy technique (4)
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1. biopsy site selection
2. biopsy technique 3. biopsy site preperation 4. fixation |
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Biopsy site selection
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multiple cutaneous representative sites
fully developed non Tx primary sites (macules, papules, pustules, nodules, neoplasms, vesicles, and wheals are most useful) secondary lesions also need to be sampled (scales, crusts, ulcers, comedones, fissures, excoriations, lichenification, pigmentary abnormalities, and scars) |
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biopsy technique ...
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a) ecisional - for lrg papules / macules
b) deeper excision for deeper lesions such as panniculitis c) digital amputation might be required for diagnosis of nail bed lesions d) NO electrocautery for sml samples e) tissue forceps to grab 1 nonaffected margin (subcutis) |
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biposy site preperation
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a) avoid surgical prep of skin at punch site (may remove diagnostic portion)
b) gentle clipping of hair OK c) excisional biopsy deep to epidermis - surgical prep OK |
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Fixation
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a) punch biopsy- 10x volume 10% NBF
b) to avoid warping - thin excision gently attach to flat object and dry 20-30 sec c) cold add 1 part alcojol to 9 parts 10% NBF d) immunoflourescence eval- place in Michel's medium- better preserves immunoglobulin & compliment e) immunoperoxidase staining can be performed on formalin fixed < 48 hrs (prolonged time = cross linking of proteins) |
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History
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a) accurate diagnosis = knowledge gross features (accurate)
age, breed, sex location, gross appearance, duration of lesion, presence or absence of symmetry and puritis |
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Response to injury is
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illistrated by changes in the epidermis, dermis, adnexa, and panniculus
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Morphology of skin lesions is seen as primary or secondary lesions.
Primary lesions are ? |
the direct result of underlying disease process, important diagnostically
include: macule, patch, papule, plaque, nodule, tumor, cyst, vesicle, bulla, pustule, abscess, or wheal |
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Macule
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a flat, circumscribed, nonpalpable spot < 1 cm in diameter w/ change in color of the skin
i.e. hemorrhage, pigmentation (lentigo, vitiligo) |
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Patch
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a macule over 1 cm in size; discoloration can be due to increase in melanin pigment
e.g hyperpigmentation in endocrine disorders, depigmentation, erythema or local hemorrhage |
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Papule
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a small (<1cm) diameter, solid elevation of the skin up to 1 cm in diameter that can be palpated as a solid mass. Papules are often pink or red swellings produced by tissue infiltration of inflammatory cells in the dermis, by intradermal and subepidermal edema, or by epidermal hypertrophy; may involve hair follicles
e.g. erythematous papules in flea bite bypersensitivity, papilloma, and superficial bacterial folliculitis |
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Plaque
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a larger, flat topped elevation, > 1cm diameter, formed by the extension or coalition of papules
e.g. calcinosis cutis, reactive histiocytosis, eosinophilic plaque |
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Nodule
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a circumscribed, firm, solid circumscribed elevation, > 1 cm diameter that usually extends into the deeper layers; usually due to infiltrations of inflammatory or neoplastic cells
e.g. bacterial or fungal infection, infectious or sterile granuloma, cutaneous lymphoma, cutaneous histiocytoma, cutaneous mast cell tumor |
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Tumor
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a large mass (neoplasia implied) that may involve any structure of the skin or subcutis; "an abnormal mass of tissue, the growth of which exceeds & is uncoordinated with that of normal tissue & persists in the same excessive manner after cessation of the stimuli, which evoked the change"
e.g. lipoma, mast cell tumor, SCC |
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Cyst
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cavity lined by epithelium & filled with liquid or semisolid material & located in the dermis or subcutis (smooth, well circumscribed, fluctuant to solid mass)
e.g. follicular cyst, dermoid cyst |
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Vesicle
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elevated, well circumscribed, fluid filled lesion < 1cm diameter, can be intraepidermal or subepidermal at the dermoepidermal junction. Vesicles are rarely seen in dogs & cats b/c they are fragile & transient
e.g. burn, viral infection, immune-mediated diseases (bulbus pemphigoid) |
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Bulla
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a large vesicle (blister) > 1cm diameter
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Pustule
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a small, circumscribed, pus filled elevation of the epidermis; can be intraepidermal, subepidermal or follicular in location; may contain:
a) predominantly neutrophils & are infectious in origin b) eosinophils e.g. in parasitic or allergic disorders c) or may be sterile e.g. pemphigus foliaceus |
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Abscess
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a well demarcated fluctuant lesion resulting from dermal or subcutaneous accumulation of pus (larger & deeper than pustules)
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Wheal
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a sharply circumscribed, elevated, irregular shaped area of cutaneous edema; blanch with pressure and usually disappears within minutes or hours
e.g. insect bites, urticaria, allergic reaction |
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Secondary lesions
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evolve from primary lesions, via self trauma, altered keratinization, etc.
include: epidermal collarette, erosion, ulcer, excoriation, scar, fissure, lichenification, and callus |
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Epidermal collarette
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a circular rim of keratin flakes following loss of the "roof" of vesicle, bulla, pustule, or papule, or the hyperkeratosis caused by focal inflammation as seen with papules and pustules
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Erosion
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loss of part of the epidermis; depressed, moist, glistening; shallow, doesn't penetrate the basal laminar zone; heals without scarring; e.g. secondary to vesicle or pustule rupture or secondary to surface trauma
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Ulcer
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loss of epidermis & basement membrane w/ exposure of dermis, concave; usually heals w/ a scar. e.g. ischemic lesions resulting from vasculitis, indolent ulcer, feline herpesvirus infection, feline ulcerative dermatosis syndrome
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Excoriation
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erosions of ulcers caused by scratching, biting, or rubbing, usually due to puritis, these lesions are self- produced. Invite secondary bacterial infection and are often recognized by their linear pattern (linear loss of epidermis)
e.g. abrasion, scratch |
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Scar
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thin to thick fibrous tissue that replaces normal skin following injury or laceration to the dermis; e.g. healed wound, surgical scar, most scars in dogs and cats are alopecic, atrophic and depigmented
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Fissure
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Linear crack or break from the epidermis to the dermis; they may be single or multiple tiny cracks or large clefts several cm long. They occur when the skin is thick and inelastic and then subjected to sudden swelling from inflammation or trauma; e.g. footpad fissure seen in pemphigus foliaceous, superficial necrolytic dermatitis, or digital hyperkeratosis
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Lichenification
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thickened epidermis secondary to persistent rubbing, scratching or irritation; these areas are often hyperpigmentation
e.g chronic dermatitis, acanthosis nigricans |
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Callus
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thick, hard, hairless plaque with increased skin creases;
e.g. often seen in trauma over bony prominence such as elbow or sternum |
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Primary or secondary lesions can be?
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Scales
Crusts Comedo Abnormalities of hair abnormalities of pigmentation/coloration |
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Scale
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fragmented, keratinized cells, flaky, skin, irregular, thick or thin, dry or oily; can be primary (e.g. idiopathic seborrhea) or secondary (e.g. chronic inflammation) also seen w/ cornification disorders, sebaceous adenitis, ichthyosis
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Crust
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an accumulation of dried exudate, serum, pus, blood, cells, scales, or medications adherent to the surface, can be primary
(e.g. primary seborrhea, zinc responsive dermatosis) or secondary (e.g. self-trauma, pyoderma, etc) |
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Nodule
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a circumscribed, firm, solid circumscribed elevation, > 1 cm diameter that usually extends into the deeper layers; usually due to infiltrations of inflammatory or neoplastic cells
e.g. bacterial or fungal infection, infectious or sterile granuloma, cutaneous lymphoma, cutaneous histiocytoma, cutaneous mast cell tumor |
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Tumor
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a large mass (neoplasia implied) that may involve any structure of the skin or subcutis; "an abnormal mass of tissue, the growth of which exceeds & is uncoordinated with that of normal tissue & persists in the same excessive manner after cessation of the stimuli, which evoked the change"
e.g. lipoma, mast cell tumor, SCC |
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Cyst
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cavity lined by epithelium & filled with liquid or semisolid material & located in the dermis or subcutis (smooth, well circumscribed, fluctuant to solid mass)
e.g. follicular cyst, dermoid cyst |
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Vesicle
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elevated, well circumscribed, fluid filled lesion < 1cm diameter, can be intraepidermal or subepidermal at the dermoepidermal junction. Vesicles are rarely seen in dogs & cats b/c they are fragile & transient
e.g. burn, viral infection, immune-mediated diseases (bulbus pemphigoid) |
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Bulla
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a large vesicle (blister) > 1cm diameter
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Pustule
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a small, circumscribed, pus filled elevation of the epidermis; can be intraepidermal, subepidermal or follicular in location; may contain:
a) predominantly neutrophils & are infectious in origin b) eosinophils e.g. in parasitic or allergic disorders c) or may be sterile e.g. pemphigus foliaceus |
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Abscess
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a well demarcated fluctuant lesion resulting from dermal or subcutaneous accumulation of pus (larger & deeper than pustules)
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Wheal
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a sharply circumscribed, elevated, irregular shaped area of cutaneous edema; blanch with pressure and usually disappears within minutes or hours
e.g. insect bites, urticaria, allergic reaction |
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Secondary lesions
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evolve from primary lesions, via self trauma, altered keratinization, etc.
include: epidermal collarette, erosion, ulcer, excoriation, scar, fissure, lichenification, and callus |
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Epidermal collarette
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a circular rim of keratin flakes following loss of the "roof" of vesicle, bulla, pustule, or papule, or the hyperkeratosis caused by focal inflammation as seen with papules and pustules
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biopsy technique ...
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a) ecisional - for lrg papules / macules
b) deeper excision for deeper lesions such as panniculitis c) digital amputation might be required for diagnosis of nail bed lesions d) NO electrocautery for sml samples e) tissue forceps to grab 1 nonaffected margin (subcutis) |
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|
biposy site preperation
|
a) avoid surgical prep of skin at punch site (may remove diagnostic portion)
b) gentle clipping of hair OK c) excisional biopsy deep to epidermis - surgical prep OK |
|
|
Fixation
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a) punch biopsy- 10x volume 10% NBF
b) to avoid warping - thin excision gently attach to flat object and dry 20-30 sec c) cold add 1 part alcojol to 9 parts 10% NBF d) immunoflourescence eval- place in Michel's medium- better preserves immunoglobulin & compliment e) immunoperoxidase staining can be performed on formalin fixed < 48 hrs (prolonged time = cross linking of proteins) |
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History
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a) accurate diagnosis = knowledge gross features (accurate)
age, breed, sex location, gross appearance, duration of lesion, presence or absence of symmetry and puritis |
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Response to injury is
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illistrated by changes in the epidermis, dermis, adnexa, and panniculus
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Morphology of skin lesions is seen as primary or secondary lesions.
Primary lesions are ? |
the direct result of underlying disease process, important diagnostically
include: macule, patch, papule, plaque, nodule, tumor, cyst, vesicle, bulla, pustule, abscess, or wheal |
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|
Macule
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a flat, circumscribed, nonpalpable spot < 1 cm in diameter w/ change in color of the skin
i.e. hemorrhage, pigmentation (lentigo, vitiligo) |
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Patch
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a macule over 1 cm in size; discoloration can be due to increase in melanin pigment
e.g hyperpigmentation in endocrine disorders, depigmentation, erythema or local hemorrhage |
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Papule
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a small (<1cm) diameter, solid elevation of the skin up to 1 cm in diameter that can be palpated as a solid mass. Papules are often pink or red swellings produced by tissue infiltration of inflammatory cells in the dermis, by intradermal and subepidermal edema, or by epidermal hypertrophy; may involve hair follicles
e.g. erythematous papules in flea bite bypersensitivity, papilloma, and superficial bacterial folliculitis |
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Plaque
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a larger, flat topped elevation, > 1cm diameter, formed by the extension or coalition of papules
e.g. calcinosis cutis, reactive histiocytosis, eosinophilic plaque |
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abnormalities of hair
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Alopecia
Hypotrichosis Atrichia Hypertrichosis Effluvium defluxion |
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Alopecia
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partial to complete loss of hair (baldness) can be primary (e.g. endocrine Dz, follicular dysplasia) or secondary ( e.g. w/ self trauma or inflammation)
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Hypotrichosis
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less hair than normal
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Atrichia
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abscence of hair (i.e. failure to develop)
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Hypertrichosis (hirutism)
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excessive growth of hair
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Effluvium
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shedding of hair
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Defluxion
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falling out of hair
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Abnormal pigmentation or coloration
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red (erythma) - inflammation/ vasodilation
black- hypermelanosis (melanoderma)/ melanotrichia (excess pigment in hair) white- hypomelanosis (leukoderma=white skin)/ leukotrichia, albinism (lack of pigment in hair) red/purple/brown/black - purpura, petechia, ecchymoses yellow- icterus blue- cyanosis |
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Response to injury (6)
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- changes in epidermis, dermis, adnexa and panniculus
- morphology of skin lesions - distribution of skin lesions - age, breed, & sex predispositions of skin diseases - vocabulary of dermatopathology -histiopathologic pattern-analysis |
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distribution of skin lesions
important diagnostic aids for skin lesions include: |
i) regional location
ii) symmetry or asymmetry |
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Age, breed, & sex predispositions of skin diseases
Many dermatologic disorders have certain predispositions: |
i) age- emodecosis, juvenille cellulitis
ii) breed- primary seborrhea of cocker spaniels, skin fold pyoderma of sharpei dogs or iii) sex- estrogen-responsive or testosterone-responsive dermatoses |
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Vocabulary of dermatopathology
a) epidermal changes |
hyperkeratosis
epidermal hyperplasia(acanthosis) epidermal hypoplasia/atrophy intRAcellular edema intERcellular edema (spongiosis) Acantholysis Exocytosis Microabscess/pustule Crust Necrosis/apoptosis Dyskeratosis hyper- & hypo pigmentation |
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Vocabulary of dermatopathology
a) epidermal changes Hyperkeratosis |
increased thickness of stratum corneum; ortho- (anuclear) or parakeratotic (nucleated)
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Vocabulary of dermatopathology
a) epidermal changes Epidermal Hyperplasia (acanthosis) |
increased thickness of the noncornified epidermis
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Vocabulary of dermatopathology
a) epidermal changes Epidermal Hypoplasia/ Atrophy |
decreased thickness of the noncornified epidermis
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Vocabulary of dermatopathology
a) epidermal changes IntRAcellular edema |
cell damage leading to hydropic/ vacuolar/ balooning degeneration
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Vocabulary of dermatopathology
a) epidermal changes IntERcellular edema (spongiosis) |
accumulation of edema fluid in the intercellular spaces
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Vocabulary of dermatopathology
a) epidermal changes Acantholysis |
loss of cohesion between epidermal cells leading to clefts, vesicles, and bullae
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Vocabulary of dermatopathology
a) epidermal changes Exocytosis |
migration of inflammatory cells through the intracellular spaces of the epidermis
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Vocabulary of dermatopathology
a) epidermal changes Microabscess/pustule |
microscopic or macroscopic cavities filled w/ inflammatory cells
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Vocabulary of dermatopathology
a) epidermal changes Crust |
surface accumulation of varying combinations of keratin, serum, cell debris, bacteria, etc
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Vocabulary of dermatopathology
a) epidermal changes Necrosis/ apoptosis |
microscopic forms of keratinocyte death
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Vocabulary of dermatopathology
a) epidermal changes Dyskeratosis |
premature or abnormal keratinization in the viable layers of the epidermis
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Vocabulary of dermatopathology
a) epidermal changes Hyper/ hypo pigmentation |
excessive or decreased amounts of melanin within the epidermis
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Vocabulary of dermatopathology
b) dermal changes include: |
collagen changes
fibroplasia/fibrosis/sclerosis dermal edema pigmentary incontinence follicular changes glandular changes vascular changes |
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vocabular of dermatopathology
b) dermal changes Collagen Changes |
hyalinization, degeneration, mineralization, etc
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vocabular of dermatopathology
b) dermal changes fibroplasia/fibrosis/sclerosis |
formation and maturation of fibrous tissue leading to scarring
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vocabular of dermatopathology
b) dermal changes Dermal edema |
widened spaces between dermal collagen, perivascular edema or lymphocytic dilation
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vocabular of dermatopathology
b) dermal changes Pigmentary Incontinence |
melanin granules free within the dermis or within dermal macrophages
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vocabular of dermatopathology
b) dermal changes Follicular changes |
include keratosis, dilation, atrophy, dysplasia, inflammation, etc
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vocabular of dermatopathology
b) dermal changes Glandular changes |
includes inflammation, atrophy, hyperplasia, cystic changes, etc
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vocabular of dermatopathology
b) dermal changes Vascular changes |
include fibrinoid degeneration, vasculitis, thromboembolism, etc
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Vocabular of dermatopathology
c) Subcutaneous Fat (panniculus adiposus) changes |
i) various reactions can occur from direct extension of similar changes in the overlying dermis
(inflammation, necrosis, fibrosis, etc) ii) or can occur in isolation from changes in the overlying skin |
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Histiopathlogic pattern- analysis
dermatitis is not ... |
dermatitis is not a particularly useful term from a diagnostic or therapeutic point of view, since the skin becomes inflammed in response to ta myriad of causes
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Histiopathlogic pattern- analysis
A method of pattern- analysis of skin lesions ... |
A method of pattern-analysis of skin lesions (at low magnification) has proved useful in relating inflammatory patterns to various types of skin diseases
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Histiopathlogic pattern- analysis
With the addition of details observed... |
With addition of details observed at higher magnification, a specific diagnosis can often be made
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Histiopathlogic pattern- analysis
Response to injury are illustrated ... |
response to injury are illustrated by changes in the epidermis, dermis, adnexa, and panniculus
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Pericascular dermatitis
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the predominant inflammatory reaction is centered on the superficial and/or deep dermal vessels
pure perivascular dermatitis spongiotic perivascular dermatitis hyperplastic perivascular dermatitis |
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pure perivascular dermatitis
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no significant epidermal changes
e.g. hypersensitivites and utricaria |
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spongiotic perivascular dermatits
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with epidermal spongiosis
e.g. hypersensitivities, contact dermatitis, ectoparasitism, seborrheic disorders,viral infections, dermatophytosis, malassezia dermatitis, etc. |
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hyperplastic perivascular dermatitis
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with epidermal hyperplasia & hyperkeratosis
common chronic dermatitis reaction which is mostly non diagnostic seen especially in chronic hypersensitivities, altered keratinization, lick dermatitis, etc |
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interface dermatitis
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- obscurring of the dermoepidermal junction by hydropic degeneration and/ or lichenoid infiltrate
- seen w/ a variety of immune mediated and/or autoimmune skin diseases, drug eruptions, viral infections (e.g. BVD, MCF, Rinderpest) |
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Vasculitis
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- neutrophilic, lymphocytic, eosinophilic or mixed
- seen w/ a variety of infections (septicemia, RMSF, Eq. viral arteritis) immune mediated Dz ( staph, drug reactions) and others |
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Nodular and diffuse dermatitis
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a) can be granulomatous, pyogranulomatous, neutrophilic, eosinophilic or mixed
b) esp. due to traumatic implantation of foreign material (hair/ plant material) or a variety of bacteria (myco) Fungi or protozoa c) for identification of specific agents, use polarization, special stains, and microbial culture |
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intradermal or subepidermal vesicular and pustular dermatitis
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a) vesicles are fragile and transient; usually evolve rapidly into pustules
b) intradermal vesicles can be due to - acantholysis -coalescing ballooning degeneration in viral dermatitis -hydropic degeneration of basal cells - intense intracellular &/or intracellular edema of the epidermis c) subepidermal vesicles can be due to - hydropic degeneration of basal cells -dermoepidermal seperation -severe subepidermal edema and/or cellular infiltration -severe intercellular edema w/ disruption of the basement membrane zone |
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perifolliculitis, folliculitis, furunculosis
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especially due to bacteria (esp. staph) fungi (esp. ringworm) or parasites (esp. demodex)
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Panicculitis
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a) variety of inflammatory cell types in lobular, septal & diffuse (both lobular and septal) patterns
b) is often an extension of an overlying nodular or diffuse dermatitis c) other causes include nutritional steatitis, injection reaction, and idiopathic |
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Atrophic dermatitis
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a) usually due to endocrine disorders and less frequently nutritional or developmental dermatoses
B) see varying combinations of orthokeratotic hyperkeratosis, epidermal atrophy, epidermal melanosis, sebacceous gland atrophy, and follicular changes (keratosis/atrophy/dilation & plugging/abscence of hair shafts/telogen predominence/increased keratinization) |
