Histopathology Flashcards

1
Q

Difference between mucocutaneous pyoderma and DLE (aside from bacteria)

A

DLE has hydropic degeneration of basal cell layer AND interface band of inflammation

MCP has interface band of inflammation WITHOUT keratinocyte cytotoxicity!

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2
Q

Difference between interface cytotoxic dermatitis and panepidermal cytotoxic dermatitis

A

Interface: basal cell layer apoptosis only

Panepidermal: Multilayer apoptosis through epidermis

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3
Q

What category of diseases are cell-poor cytotoxic (interface) dermatitis

A

Chronic vasculopathies, Ischemic dermatopathy like dermatomyositis

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4
Q

2 causes for hydropic degeneration

A

Cell rich: CD8 T cells and NK cells mediate apoptotic cell death

Cell poor: hypoxia 2’ chronic vascular damage. Induces endoplasmic reticulum stress + autophagy

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5
Q

Where on the body are plasma cells present in cytotoxic interface dermatitis

A

Mucosal, mucocutaneous lesions

(otherwise, usually just lymphocytic +/- DCs, macrophages)

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6
Q

What are “sunburn cells”

A

Apoptotic keratinocytes 2’ UV damage. Usually in stratum spinosum. NO SATELLITOSIS w/T cells.

-CLE, photodermatoses

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7
Q

Which cytokine do Th1 CD4 T cells, CD8 T cells, ILC1, NK, NK-T cells produce

A

IFNg

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8
Q

Which cytokine is upregulated in dogs with CLE

A

IFNg

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9
Q

Which chemokine is upregulated in dogs with CLE

A

CXCL10 (made by T cells, keratinocytes)

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10
Q

Which diseases have confluences of apoptotic keratinocytes in the epidermis

A

SJS/TEN (but dermis is NORMAL)

Thermal burn (but dermis is ABNORMAL/ulcerated)

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11
Q

What causes thickening of the BMZ in DLE, MCLE, hyperkeratotic EM

A

Deposition of immunglobulins and immune complexes

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12
Q

What may cause dermal mucinosis in DLE

A

Keratinocytes upregulate versican 1 d/t IFNg stimulation

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13
Q

Cytotoxic panepidermal dermatitis with parakeratosis diseases [follicular infundibular epithelium severely affected + satellitosis] (4)

A

*Feline proliferative and necrotizing otitis externa
*Infiltrative mural folliculitis and dermatitis with apoptosis and parakeratosis (black labs)
*Hyperkeratotic EM
*Superficial necrolytic dermatitis

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14
Q

Acanthosis definition

A

Thickening of the stratum spinosum

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15
Q

Where are arrector pili muscles on the body

A

Dorsum

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16
Q

Animals with simple hair follicles

A

*Human
*Cattle
*Horse
*Pig

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17
Q

Animals with compound hair follicles

A

*Dog
*Cat
*Sheep
*Goat

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18
Q

Which animal has a thick connective tissue layer in the deep dermis

A

Horses

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19
Q

Where is skeletal muscle present in the skin?

A

Muzzle, forehead, eyelids, perianal region

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20
Q

Where is the stratum lucidum visible in dogs?

A

Pawpads

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21
Q

General causes for necrosis vs apoptosis

A

Apoptosis: immune-mediated

Necrosis: photosensitization, burn, TEN

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22
Q

Which protein and cells are implicated in TEN (full thickness epidermal necrosis)

A

Granulysin from CD8+ T cells and NK cells

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23
Q

Stain for mycobacteria

A

Acid fast, Fite

(short rods, filamentous)

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24
Q

Stain for Burkholderia

A

Warthin-Starry

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25
Stain for oomyctes
GMS
26
IHC marker for epithelial cells
Cytokeratin
27
IHC marker for mesenchymal cells
Vimentin
28
IHC marker for T cells
CD3
29
IHC marker for B cells
CD20 PAX5 CD79a
30
IHC marker for histiocytes
Iba1 CD18
31
Where on the body is there minimal SC fat
Limbs
32
How to distinguish mucin from solar elastosis
Both are lightly basophilic areas in the upper dermis Solar elastosis: can still see the thin fibers Mucin: no fibers, more generalized, smudgy blue
33
Histopath for acral lick dermatitis
*Vertical dermal fibrosis, streaking *Acanthosis *Compact hyperkeratosis (ortho or parakeratotic)
34
Histopath for eosinophilic plaque
*Epidermal hyperplasia *Spongiosis *Exocytosis of eosinophils *Perivascular eosinophilic dermatitis
35
Histopath of psoriasiform lichenoid dermatosis
*Psoriasiform epidermal hyperplasia *Cocci in crust 2' cyclosporine OR English Springer Spaniel w/Staph hypersensitivity
36
Which virus has intraNUCLEAR inclusion bodies
Herpes Papilloma (DNA viruses)
37
Which virus has intraCYTOPLASMIC inclusion bodies
Poxvirus
38
Disease in a goat with intracytoplasmic inclusion bodies
Poxvirus Contagious ecthyma "Orf" Spontaneous regression in 1 month Zoonotic
39
How can you differentiate sebaceous adenitits from Leishmania?
Sebaceous adenitis has granulomatous/pyogranulomatous sebaceous adenitis with NO nodular dermatitis. Negative IHC for Leishmania Leishmania has NODULAR to DIFFUSE dermatitis in addition to the sebaceous gland involvement. + IHC for Leishmania spp.
40
Diseases where sebaceous glands are destroyed as secondary targets
*Sterile granuloma and pyogranuloma syndrome *Juvenile sterile granulomatous dermatitis and lymphadenotitis *Uveodermatologic syndrome *Demodicosis *Canine Leishmania Idiopathic sebaceous adenitis (dogs, humans, cats, rabbits, horses) = cell-mediated destruction of sebaceous glands.
41
Breeds for sebaceous adenitis
*Standard poodle (autosomal recessive) *Akita (autosomal recessive) *Samoyed *Vizsla *Dachshund
42
Infundibular keratinizing acanthoma
43
Trichoblastoma
44
Inferior tricholemmoma
45
Pilomatricoma
46
Trichoepithelioma
47
Guinea pig
Trichofolliculoma
48
Follicular cyst
49
Dog. Crusted pawpad
Pemphigus foliaceus Broad subcorneal pustules with acantholytic keratinocytes, well-preserved neutrophils +/- eosinophils DSC1
50
Dog. Deep ulcers on mucosal surfaces
Pemphigus vulgaris Vesicles, suprabasilary clefting with tombstoning of basal keratinocytes. Hemorrhage and serocellular exudate in the clefts. Usually, mucous membranes affected, but MAY involve hair follicles DSG3 Type 2 hypersensitivity
51
Dog. Young. Ulcerate lesions on concave pinnae, oral cavity, footpads, nasal skin Erosions and ulcers on axillae, abdomen, inguinum
Junctional Epidermolysis Bullosa Laminin 332 --> split through the lamina lucida. Minimal to no inflammation PAS on DERMAL side (stains lamina densa) Ulcerated paw pads, pressure points
52
Dog. Well-demarcated, hyperkeratotic, alopecic plaques
Darier's Disease Suprabasilar clefting due to profound acantholysis. NO neutrophils. Acantholytic keratinocytes = corp ronds Bernese Mountain dogs overrepresented?? ATPA2 gene, SERCA2 ATPase pump located in endoplasmic reticulum Autosomal dominant
53
Young GSHP
Exfoliative cutaneous lupus erythematosus Cell poor interface dermatitis AND sebaceous adenitis Nearly identical histopath to feline thymoma-associated exfoliative dermatitis 1/3 have lymphadenomegaly. Many develop arthralgia. Infertile. A`nemia, fluctuating thrombocytopenia. (Variant of SLE?)
54
Dog. Erythematous macules, papules, plaques on haired skin, foot pads, pinnae, MM
Erythema multiforme Lymphoplasmacytic interface dermatitis with transepidermal apoptosis, lymphocytic satellitosis +/- erosions/ulcers +/- parakeratosis Idiopathic vs drug induced. Type 4 hypersensitivity targeting KCs.
55
Collie. Ulcers on ventral abdomen
Vesicular cutaneous lupus erythematosus Lymphoplasmacytic interface dermatitis with apoptosis of basal keratinocytes. May have erosions/ulcers with vesicle formation Collies, Shelties
56
Cat. Old age.
Thymoma-associated exfoliative dermatitis Lymphoplasmacytic interface dermatitis with apoptosis of basal +/- spinous KCs. May affect follicular epithelium. NO SATELLITOSIS (differentiate from EM). LOSS OF SEBACEOUS GLANDS. Orthokeratotic hyperkeratosis Exfoliation on head, neck, pinnae --> general. Not always paraneoplastic. Can occur in rabbits, goats too! **MALASSEZIA YEAST OVERGROWTH ON CYTOLOGY**
57
Dog. Onychomadesis
Symmetric lupoid onychodystrophy Cell poor lymphoplasmacytic interface dermatitis. Pigmentary incontinence. Apoptosis of basal keratinocytes. D-E junction "unzipping" * Histopath unlikely to be on boards
58
Dog. Middle-aged. Nasal planum.
Discoid lupus erythematosus Lymphoplasmacytic lichenoid-interface dermatitis. Basal cell apoptosis. Pigmentary incontinence Need clinical correlate to differentiate from mucocutaneous pyoderma
59
Pemphigus foliaceus
60
Stain to confirm AISBD?
PAS (can also do Collagen 4 IHC, or salt-split immunofluoresence)
61
Dog. Crusts, erosions/ulcers, on paw pads, pressure points, MC junctions
Hepatocutaneous Syndrome Red = parakeratosis White = laminar edema Blue = basal cell hyperplasia Liver: Honey comb on AUS. Hypoaminoacidemia, decreased serum essential fatty acid levels
62
Bird
Avian pox Opaque, yellow papular lesions on head, MM Epidermal hyperplasia with hydropic degeneration. Eosinophilic intracytoplasmic inclusion bodies (Bollinger bodies) in KCs.
63
Cat. Well-demarcated, raised, erythematous plaques on abdomen, thighs.
Eosinophilic plaques Severe acanthosis with moderate spongiosis of epidermis, follicular epithelium. Accumulation of mucin. Perivascular to diffuse eosinophilic dermatiits R/o FAD, CAFR, AD
64
Cat. Ulcerations on face, nasal planum
Feline Herpesviral Dermatitis Ulcerative dermatitis. Intranuclear viral inclusions in KCs (within the ulcer) with severe eosinophilic dermatitis FHV-1. Latency in Trigeminal ganglia.
65
Dog. Raised nodular mass on distal limb
Acral lick dermatitis Erosion/ulceration with acanthosis and furunculosis. Free hair shafts embedded within pyogranulomatous dermatitis. Hyperplastic apocrine glands. +/- bacterial folliculitis or on the surface (licking) *Check for demodex or dermatophytes
66
Dog on cyclosporine.
Psoriasiform Lichenoid Dermatosis 1) Spontaneous in springer spaniels. 2) 2' Cyclosporine in any breed Staph hypersensitivity reaction pattern?? Lymphoplasmacytic lichenoid dermatitis with papillary epidermal hyperplasia, hyperkeratosis, Munro's microabscess (neutrophilic pustule in epidermis), and cocci Multifocal, well-circumscribed hyperkeratotic and alopecic papules, plaques. Concave pinnae
67
Disease with Munro's microabscesses
Psoriasiform lichenoid dermatosis (neutrophilic pustule)
68
Young Golden retriever
Ichthyosis- nonepidermolytic Orthokeratotic hyperkeratosis; brightly eosinophilic, densely compacted keratin-- tightly adherent Golden retriever: Type 1: PNPLA-1. Autosomal recessive Type 2: ABHD5. Autosomal recessive. More severe. 2' bacterial, malassezia infx
69
Young norfolk terrier
Epidermolytic ichthyosis Acanthosis with prominent granular cell layer. Vacuolation, lysis of kerationcyte in granular/spinous layers. Orthokeratotic hyperkeratosis (not as compacted as non-epidermolytic ichthyosis) Pigmented scale, hyperkertotic plaques in inguinum since birth Norfolk Terrier. KRT10. Autosomal recessive
70
Vizsla
Sebaceous adenitis Lymphoplasmacytic periadnexal dermatitis with loss of sebaceous glands. Orthokeratotic hyperkeratosis and follicular keratosis Standard Poodle, Akita, Vizsla (nodular variant), Havanese
71
Husky
Zinc responsive dermatosis Marked parakeratosis with acanthosis and patchy loss of granular cell layer. Parakertosis extends into follicular ostia. Spongiosis and perivascular to interstitial dermatitis Breeds: Arctic dogs. NEW: Frenchies, Boston Terriers on pinnal margins!
72
Dog. Nasal planum
Proliferative Nasal Arteritis Ulceration, fissuring. Thickened arterioles underneath ulcer bed. Marked thickening of tunica intima with spindle cells, mucinosis. +/- thrombi. Saint Bernard, GSD
73
Akita
Uveodermatologic syndrome (VKH) Histiocytic and lymphoplasmacytic LICHENOID inflammation w/ "fine dusting" of melanin within macrophage (pigmentary incontinence). Depigmentation/ leukotrichia/ ulcers in Chow Chow, Akita, Malamutes, Husky, Samoyeds Uveitis --> blindness
74
Boxer. Nodular mass on pinna
Canine Leproid Granuloma Granulomatous to pyogranulomatous nodular dermatitis. Acid fast + bacteria in macrophages. Difficult to culture. Enters skin 2' trauma.
75
Pinna mass on boxer. Diagnosis?
Leproid granuloma Negatively staining cytoplasm of macrophages Non-tuberculous mycobacterium (pic = PAS histo)
76
Diagnosis?
Leishmania Leishmania has perpendicular kinetoplast Trypanosoma has parallel kinetoplast
77
Dog or cat from TX
Leishmania Pyogranulomatous inflammation. Parasitophorous vacuoles filled with Leishmania amastigotes. LOSS OF SEBACEOUS GLANDS Giemsa stain In the USA: Leishmania mexicana (cats) cause nodular swellings on the pinnae and face. Zoonotic. Natural host in TX = woodrats
78
Immunosuppressed dog or cat. Gram +, Weakly acid fast
Nocardiosis Pyogranulomatous dermatitis/cellulitis with rare colonies of branched filamentous bacteria. Gram +, weakly acid fast. (Actinomyces is NOT acid fast)
79
PERSIAN Cat. SQ nodule on trunk, dorsal tail.
Dermatocytic pseudomycetoma Pyogranulomatous nodular dermatitis with intralesional aggregates of non-pigmented fungal hyphae. +/- Splendore-Hoeppli phenomenon. Stains + with GMS, PAS Microsporum canis. (Fungal kerion on face if this was a dog). Pseudomycetoma = organism in tissue as grains, but NOT mycelial formation.
80
Cat. Bridge of nose
Cryptococcus Granulomatous inflammation with "soap bubble" appearance-- unstained, thick heterpolysaccharide capsule. Narrow-based budding Clinical: Roman nose. Can occur in immunoCOMPETENT animals Stain: Mayer's mucicarmine (also PAS, GMS)
81
Horse or cat. Raised dermal nodules
Pheohyphomycosis Pyogranulomatous inflammation with pigmented fungal hyphae. Dermal, SC masses on face, distal extremities w/ draining tracts. Stain = Fontana-Masson to highlight melanin in hyphae Cats, Horses that are immunCOMPETENT. Dogs are immunosuppressed. GSD predisposed. ABCCEO A=Alternaria B=Bipolaris C=Cladosporium C=Curvularia E=Exophiala O=Ochroconis
82
Horse
Habronemiasis, "Summer Sores" Nodular to diffuse, granulomatous/ eosinophilic dermatitis with erosion, ulceration. 50% have Habronema larva Firm, proliferative nodular lesions w/yellow debris. Periocular. Habronema muscae, Habronema majus, Draschia megastoma (Vector = stable fly, house fly)
83
Opaque, white nodules on cat
Xanthomatosis Nodular to diffuse foamy extracellular lipid lakes, acicular cholesterol clefts, granulomatous inflammation, multinucleated giant cells (Touton's type) Abnormal lipid metabolism, high fat diet, Diabetes mellitus, hypothyroidism.
84
Cat pawpad
Plasma cell pododermatitis, nasal dermatitis Dense sheets of plasma cells, variable Mott cells. Occasional eos, neuts PAS stain highlight Mott cells- Russel bodies are rich in carbohydrates **50% cats are FIV +!!!** Elevated globulins on Chem. Possible concurrent plasma cell stomatitis, immune-mediated glomerulonephritis, renal amyloidosis.
85
English bulldog. Dorsal neck.
Calcinosis cutis Deeply basophilic mineral throughout the superficial/mid-dermis. Granulomatous inflammation. Transepidermal elimination of mineral. HAC Bone in late stages = osteoma cutis
86
Dog, cat. Scaly, alopecia
Dermatophytosis Multifocal pyogranulomatous folliculitis and furunculosis with dermatophytic hyphae +/- arthrospores. May see pustular variant with acantholytic keratinocytes (Trichophyton)
87
Dog
Demodicosis Pyogranulomatous mural folliculitis and furunculosis with pigmentary incontinence and intrafollicular mites
88
Dog. Dorsum.
Post grooming furunculosis Pyogranulomatous furunculosis with hemorrhage and edema. Hemorrhagic bullae with fibrin within dermis PAINFUL. Pseudomonas aeruginosa usually. Bath 1-2d before presentation
89
Dog
Alopecia areata Swarm of bees around anagen hair follicle = lymphoplasmacyticbulbitis. +/- perifollicular fibrosis. Associated with autoantibodies and complement around hair follicles. IgM, IgG to hair follicle antigens in circulation. (Pseudopelade affects isthmus, bulge area)
90
Dog
Canine Cushing's disease Epidermal atrophy. Thin walled comedones. Follicular atrophy. +/- sebaceous gland atrophy. Boston Terrier, Boxer, Dachshund, Mini poodle endogenous HAC. English bulldog iatrogenic HAC.
91
Pomeranian
Alopecia X Epidermal atrophy w/ orthokeratotic hyperkeratosis in loose pattern. Telogenization of hair follicles w/flame figures and prominent tricholemmal keratin Possible etiology: Late-onset deficiency of 21-hydroxylase leading to progestin and androgen excess at puberty
92
Cat. Systemically unwell. NOT FRAGILE skin, but wrinkled and thin
Feline paraneoplastic alopecia Miniaturization of follicles (telogenization) and follicular atrophy. Acanthosis. Partial loss of stratum corneum Shiny skin, painful pawpads. NOT FRAGILE skin, but wrinkled and thin Pancreatic carcinoma Malassezia pachydermatis infections!!
93
Bulldog
Hyperpigmented epidermis. Follicular keratosis. Atrophy of the lower portion of the hair follicle = "inverted witch's foot". Boxers, bulldogs. Spring time.
94
Dog
Black Hair follicular dysplasia Melanin clumping in hair shafts with breakage at the sites of clumping. Pigmentary incontinence around anagen hair bulbs.
95
Mini poodle
Post-rabies vaccination panniculitis 1) Follicular ischemic atrophy 2) Multifocal lymphoid nodules in panniculus 3) Amphophilic adjuvant substrate in subcutis Poodles over-represented. "Poodle patch". Right rear thigh, but can have lesions away from vaccine spot.
96
Pug
Pigmented viral plaque Orderly maturation of keratinocytes D/E junction has scalloped appearance. Hyperpigmentation, enlarged keratohyalin granules. No viral inclusions **CPV-9** CPV-4, CPV-8 Pugs, Mini schnauzers, Boston Terrier, Frenchies. Can progress to trichoepithlioma or SCC
97
Horse
Squamous cell carcinoma Infiltrative beyond the BMZ, unencapsulated lobules of epithelial cells with multifocal keratin pearls. Anisocytosis, Anisokaryosis. Mitotic activity HIGHER than IKA. +/- Solar elastosis. UV light. Cancer eye in Hereford cattle. Paint horses. Non-pigmented skin in cats (nasal planum, pinnae, eyelids)
98
10 yo cat
Bowenoid in situ carcinoma RESPECTS BMZ Hyperplastic and dysplastic epithelial without breaking through BMZ. No viral inclusions **Associated with FcPV-2**
99
Dog
Canine Ribbon-Type Trichoblastoma Basal cell tumor
100
Cat
Feline Trabecular-type Trichoblastoma Basal cell tumor Often pigmented in cats
101
Older cat front paw
Metastatic Pulmonary Carcinoma Multifocal tubules lined by ciliated respiratory epithelium w/goblet cells. May infiltrate ST and bone. Chest rads: Single, large circumscribed mass in CAUDAL LEFT lung field. Paw Radiograph: osteolysis of digit.
102
Horse
Equine sarcoid Epidermal rete ridge formation that extends into deep dermis. "Picket fence" pattern: perpendicular fibroblasts relative to BMZ **BPV 1, BPV2. Major transforming viral protein = E5** E5 downregulates MHC 1 --> evade immune destruction by CD8 T cells
103
Old dog
Cutaneous epitheliotropic lymphoma Neoplastic lymphocytes w/tropism for epithelium, esp follicular epithelium and apocrine sweat glands. Usually lower 1/2 epidermis. Pautrier's microabscesses. IHC= CD3+ T cells PARR for clonality