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Histopathology (not done) Flashcards

1
Q

Besides interface dermatitis, what other histopath feature typically occurs in ECLE?

A

Sebaceous adenitis

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2
Q

How does histopath of dermatomyositis differ from that of VCLE?

A

Dermatomyositis: cell POOR interface dermatitis + ischemic follicular atrophy
VCLE: Lymphocyte RICH interface dermatitis without ischemia

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3
Q

Where does the vesiculation occur in VCLE on histopath?

A

Intrabasal

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4
Q

What is are characteristic histopath features of cutaneous lupus?

A

Lymphocyte-rich interface dermatitis with basal keratinocyte damage

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5
Q

What is the histopathologic hallmark of canine sarcoidosis?

A

Naked granulomas (i.e. macs without lymphocytes at the periphery of the granuloma)

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6
Q

How would you differentiate histiocytoma from reactive histiocytosis on histopath?

A

Histiocytoma is top-heavy and the neoplastic cells have epitheliotropism

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7
Q

Is a lymphoplasmacytic lichenoid dermatitis specific for discoid lupus erythematosus?

A

No – this inflammatory pattern can be reflective of ANY mucosal inflammation (so need to look for other features like basal cell damage)

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8
Q

Describe the key histopath features of EM

A

1) Cytotoxic interface dermatitis
2) multi-level/transepidermal apoptosis
3) lymphocytic satellitosis

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9
Q

What is a primary difference between EM and TEN on histopath?

A

Less inflammation and more necrosis in TEN

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10
Q

How is TEN distinguished from a burn on histopath?

A

TEN lacks dermal necrosis (but epidermal necrosis is a feature of both

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11
Q

How is EM distinguished from lupus erythematosus on histopath?

A

Lupus: apoptosis limited to basal layer

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12
Q

How can you use sebaceous glands to differentiate a biopsy of a dog from that of a cat?

A

Sebaceous glands: Dogs have vacuolated seb glands, cats have neat tidy sebaceous glands

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13
Q

How can you use hair follicles to differentiate the species on biopsy?

A
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14
Q

You find skeletal muscle on biopsy. Where is it likely from?

A

Face (chin) or perianal

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15
Q

You find arrector pili muscle on biopsy. Where is it likely from?

A

Dorsum

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16
Q

A biopsy has a thickened epidermis with a stratum lucidum present. Where was it taken from?

A

Paw pad

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17
Q

You find a sinus hair on a biopsy. Where is it from?

A

Face (OR carpus in cats)

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18
Q

What stains could you recommend to assess for Mycobacteria?

A

Acid-fast
Fites

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19
Q

What stains could you recommend to assess for mast cells?

A

Toluidine blue
Giemsa

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20
Q

What IHC can be used for epithelial neoplasms?

A

Cytokeratin

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21
Q

What IHC can be used for mesenchymal neoplasms?

A

Vimentin

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22
Q

What IHC can be used to highlight T-cells?

A

CD3

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23
Q

What IHC can be used for histiocytes?

A

CB18/Iba-1

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24
Q

What IHC can be used for B-cells?

A

CD20
CD79a
CD79b
Pax5

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25
Q

Describe the histopathologic findings for Golden Retriever ichthyosis

A

Lamellar orthokeratotic hyperkeratosis, no inflam, no epidermal hyperplasia

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26
Q

Describe the histopath features of acral lick granuloma

A

Irregular hyperplasia of the epidermis and follicular infundibula
Compact hyperkeratosis and multifocal parakeratosis
Vertical streaking

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27
Q

What is another name for intercellular edema on histopath?

A

Spongiosis

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28
Q

What is another name for intracellular edema on histopath?

A

Ballooning degeneration

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29
Q

What is hydropic degeneration?

A

Intracellular edema of the BASAL cell layer

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30
Q

Where are inclusion bodies found for poxvirus?

A

Within the cytoplasm

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31
Q

Where are inclusion bodies found for herpesvirus?

A

Within the nucleus

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32
Q

What is acanthosis?

A

Thickening of the epidermis

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33
Q

Describe the histopathologic findings of uveodermatologic syndrome

A

Lichenoid to interface histiocytic dermatitis
Pigmentary incontinence

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34
Q

What phase is this hair in?

A

Telogen (retraction of papilla, trichilemmal keratinization)

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35
Q

What glands are highlighted in this image?

A

Epitrichial (dog paw pad)

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36
Q

How could you confirm a vessel is a lymphatic vessel on histopath?

A

Use LYVE-1 stain

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37
Q

What is a unique feature of feline herpesvirus on histopath?

A

Necrosis of epitrichial sweat glands

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38
Q

Where are inclusion bodies found on histopath of FHV?

A

Intranuclear within keratinocytes/histiocytes

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39
Q

Where are inclusion bodies found in distemper virus?

A

Keratinocyte cytoplasm (intranuclear rare)

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40
Q

Histopathology from a horse dorsum reveals luminal folliculitis and dermatitis with palisading crusts and gram-positive cocci in branching filaments. What is the most likely cause of this?

A

Dermatophilosis congolensis

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41
Q

How could you differentiate a cat with endocrine alopecia from one with paraneoplastic alopecia on histopath?

A

Paraneoplastic: Follicular and adnexal atrophy + epidermal HYPERPLASIA
Endocrine: Follicular and epidermal ATROPHY

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42
Q

What other condition does feline thymoma-associated exfoliative dermatitis resemble on histopath?

A

Erythema multiforme

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43
Q

What is the term for excessive trichilemmal keratinization?

A

Flame figure

44
Q

Describe the histopathologic findings in SND

A

Parakeratotic hyperkeratosis (red)
Intra- and intercellular edema (white)
Basal cell hyperplasia (blue)

45
Q

What histochemical stains can be used to highlight mast cells on biopsy?

A

Giemsa
toludine blue

46
Q

What is the typical description of the basal cell layer in Bowen’s disease?

A

“Wind swept” appearance

47
Q

Describe 2 major histopath findings for SCC

A

Cords of dysplastic keratinocytes in dermis
Keratin pearls

48
Q

What conditions are associated with keratin pearls on histopath?

A

SCC
Follicular cyst
IKA

49
Q

What histopathologic feature can help differentiate between plasmacytoma and histiocytoma?

A

presence of Grenz zone in plasmacytoma

50
Q

What is a Grenz zone?

A

Narrow area of unaffected dermis seen in some dermal neoplasms (separates unaffected epidermis from affected dermis –> plasmacytomas)

51
Q

You are trying to differentiate between histiocytoma and cutaneous reactive histiocytosis on histopath. How does the distribution of cells help with this?

A

Histiocytoma: top-heavy (epitheliotropism)
Histiocytosis: Bottom-heavy

52
Q

What marker is lacking in cutaneous reactive histiocytosis that can help differentiate it from a histiocytoma?

A

E-cadherin

53
Q

Define pagetoid reticulosis

A

Epitheliotropic lymphoma limited to the epidermis

54
Q

Define mycosis fungoides

A

Epitheliotropic lymphoma that invades that epidermis, hair follicle, AND dermis

55
Q

You are examining slides of a cutaneous round cell tumor that is limited to the dermis and SQ and has a top-heavy configuration. What is the most likely tumor?

A

Histiocytoma

56
Q

You are examining slides of a cutaneous round cell tumor that is limited to the dermis and SQ, bottom heavy, with a Grenz zone present. What are the top differentials?

A

1) Plasmacytoma
2) Non-epitheliotropic lymphoma

57
Q

You are examining slides of a cutaneous round cell tumor without a top-heavy configuration and without a Grenz zone. What are your top differentials?

A

MCT
CETL
Histiocytic sarcoma
TVT

58
Q

What protein is mutated in canine MCT?

59
Q

What immunohistochemical stains help differentiate histiocytoma from reactive histiocytosis?

A

Histiocytoma: positive E-cadherin, negative Thy-1 and CD4

60
Q

What is the term for focal accumulations of atypical lymphocytes within the epidermis (i.e. as seen in CETL)?

A

Pautrier microabscesses

61
Q

What type of tumor has a “picket-fence” configuration of spindle cells abutting the epidermis?

A

Equine/feline sarcoids

62
Q

What differentiates sebaceous hyperplasia from sebaceous adenoma on histopath?

A

Sebaceous hyperplasia: retention of normal orientation of seb glands around ducts/follicular infundibulum, no degeneration/dropout of mature sebocytes

63
Q

What feline condition does ECLE resemble on histopath?

A

Exfoliative dermatitis

64
Q

What condition is associated with Touton cells?

65
Q

Where are inclusions found in avian poxviruses?

A

Eosinophilic intracytoplasmic inclusions (Bollinger bodies)

66
Q

What are the top differentials for cytotoxic interface dermatitis?

A

Cutaneous lupus (any form)
Ischemic dermatopathy
Fixed drug reaction
Lupoid onychitis
Pemphigus erythematosus
VKH
Erythema ab igne
CETL (very rare)

67
Q

What are the top differentials for a panepidermal cytotoxic dermatitis?

A

EM
SJS
TEN
PNOE
thymoma-associated exfoliative dermatitis
CETL
Staph toxic shock syndrome

68
Q

What part of the body tend to have a lichenoid band with ANY form of inflammatory disease?

A

MC junctions

69
Q

What are the top differentials for lichenoid inflammation WITHOUT cytotoxic changes?

A

Any mucocutaneous junction inflammatory disease (including MCP)
Psoriasiform-lichenoid dermatitis

70
Q

What type of follicular tumor has a medusoid pattern?

A

Trichoblastoma (these tumors are not typically cystic)

71
Q

What breeds are predisposed to IKAs?

A

Norwegian Elkhounds
GSDs

72
Q

What follicular tumor is characterized by “ghost cells”?

A

Pilomatricoma

73
Q

What type of follicular tumor is more likely to have mineralization: pilomatricoma or trichoepithelioma?

A

Pilomatricoma (very uncommon to see mineralization in trichoepitheliomas)

74
Q

True or false: Bowenoid in situ carcinoma can be solar induced

A

False - Bowenoid implies it is VIRAL-induced

75
Q

What are the clinical characteristics of Bowenoid in situ carcinomas?

A

Fully haired areas
Multicentric
(Bowenoid carcinomas are NOT solar-induced carcinomas)

76
Q

In what condition might you find fine pigment dusting within macrophages?

77
Q

You find the highlighted area on histopath from a neoplastic region. What is the feature and what is this most consistent with?

A

Keratin pearl– SCC

78
Q

There is a “swarm of bees” pattern surrounding the inferior segment of an anagen follicle. What is the likely diagnosis?

A

Alopecia areata

79
Q

What is being demonstrated by the red line in this image?

A

Transepidermal elimination

80
Q

What is the term used for inflammation in apocrine glands?

A

Hidradenitis

81
Q

What histologic stains can be used to highlight mucin?

A

Mucicarmine
Alcian blue
Ferric iron
Muscarinic acid

82
Q

What is highlighted in the circled areas?

A

Colonies of coccoid bacteria

83
Q

You obtain this histology from a dog with a facial-predominant crusting dermatosis. What is the most likely diagnosis?

A

Zinc-responsive dermatosis

84
Q

What is the most likely breed for this biopsy?

A

Shar Pei (Shar Pei mucinosis)

85
Q

What histopathologic features are consistent with a facial origin?

A

Increased # of sebaceous glands
Sinus hairs
Possible skeletal muscle present

86
Q

What is highlighted by the red line and what is the most likely diagnosis?

A

Pautrier’s microabscesses (intraepidermal lymphocytic aggregates)
CETL

87
Q

What is being demonstrated by the circled area in this photo?

A

Variably sized keratohyalin granules (think viral)

88
Q

What are the structures highlighted in this photo?

A

Koilocytes

89
Q

What is being demonstrated in this photo and what is the likely cause?

A

Intranuclear inclusion body
Likely viral infection

90
Q

What is a cevatte body?

A

An apoptotic keratinocyte present in the basal cell layer of the epidermis

91
Q

What species did this likely come from?

A

Horse (eccrine glands)

92
Q

What part of the body did this likely come from?

A

MC junction (skeletal muscle, few HF, deep rete ridges, thick epidermis)

93
Q

What condition is consistent with parakeratotic capping and papillary squirting?

94
Q

You find the following on histopathology from a nodule on a dog trunk. What is the diagnosis?

95
Q

Where on the body did this biopsy likely come from?

A

Paw pad (non-haired skin, hyperkeratosis, adipose tissue, presence of eccrine sweat glands would also help)

96
Q

Are the melanin changes in this biopsy normal or abnormal and why?

A

Abnormal: melanin clumping in bulb can be normal for a dilute dog but should NOT see melanin outside the HF in normal dog (this is likely CDA)

97
Q

What special stain is this and what is it highlighting?

A

GMS – elastin

98
Q

This biopsy is from a cat. What stain was likely used and what is the most likely diagnosis?

A

Fites stain- mycobacteria

99
Q

In what part of the tissue should you look if you are trying to diagnose Mycobacteria in a cat?

100
Q

This biopsy came from a dog pinna. What is the likely diagnosis?

A

Leproid granuloma (Fites/Ziehl Nielson stain)

101
Q

What species did this biopsy likely come from?

A

Horse (abundant sebaceous gland, simple HF)

102
Q

This biopsy came from a cat. What is the highlighted cell and what is the most likely diagnosis?

A

Mott cell (plasma cell filled with Ig)
Plasma cell pododermatitis

103
Q

A dog presented with numerous silvery, scaly lesions and the following finding on biopsy. What is the gold standard diagnostic test based on your suspected dx?

A

PCR of LN/bone marrow (this is likely Leishmania – image shows macs filled with granular material which is the kinetoplasts)

104
Q

A cat is presented with draining tracts, fever, and lameness. What is the most likely diagnosis based on this image?

A

Coccidiodomycosis (endosporulation apparent, diagnostic feature of Coccidiodomycosis)

105
Q

You find the circled organism on histopath. What is the most likely diagnosis?

A

Prototheca (internal septations)

106
Q

You see the following changes on histopathology. What stain could be applied to highlight the suspected cause?

A

Mucicarmine (stains cryptococcus capsule)

MK ACVD Exam (17 decks)

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