Histopathology (not done) Flashcards
1
Q
Besides interface dermatitis, what other histopath feature typically occurs in ECLE?
A
Sebaceous adenitis
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
3
Q
Where does the vesiculation occur in VCLE on histopath?
A
Intrabasal
4
Q
What is are characteristic histopath features of cutaneous lupus?
A
Lymphocyte-rich interface dermatitis with basal keratinocyte damage
5
Q
What is the histopathologic hallmark of canine sarcoidosis?
A
Naked granulomas (i.e. macs without lymphocytes at the periphery of the granuloma)
6
Q
How would you differentiate histiocytoma from reactive histiocytosis on histopath?
A
Histiocytoma is top-heavy and the neoplastic cells have epitheliotropism
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)
8
Q
Describe the key histopath features of EM
A
1) Cytotoxic interface dermatitis
2) multi-level/transepidermal apoptosis
3) lymphocytic satellitosis
9
Q
What is a primary difference between EM and TEN on histopath?
A
Less inflammation and more necrosis in TEN
10
Q
How is TEN distinguished from a burn on histopath?
A
TEN lacks dermal necrosis (but epidermal necrosis is a feature of both
11
Q
How is EM distinguished from lupus erythematosus on histopath?
A
Lupus: apoptosis limited to basal layer
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
13
Q
How can you use hair follicles to differentiate the species on biopsy?
A
14
Q
You find skeletal muscle on biopsy. Where is it likely from?
A
Face (chin) or perianal
15
Q
You find arrector pili muscle on biopsy. Where is it likely from?
A
Dorsum
16
Q
A biopsy has a thickened epidermis with a stratum lucidum present. Where was it taken from?
A
Paw pad
17
Q
You find a sinus hair on a biopsy. Where is it from?
A
Face (OR carpus in cats)
18
Q
What stains could you recommend to assess for Mycobacteria?
A
Acid-fast
Fites
19
Q
What stains could you recommend to assess for mast cells?
A
Toluidine blue
Giemsa
20
Q
What IHC can be used for epithelial neoplasms?
A
Cytokeratin
21
Q
What IHC can be used for mesenchymal neoplasms?
A
Vimentin
22
Q
What IHC can be used to highlight T-cells?
A
CD3
23
Q
What IHC can be used for histiocytes?
A
CB18/Iba-1
24
Q
What IHC can be used for B-cells?
A
CD20
CD79a
CD79b
Pax5
25
Describe the histopathologic findings for Golden Retriever ichthyosis
Lamellar orthokeratotic hyperkeratosis, no inflam, no epidermal hyperplasia
26
Describe the histopath features of acral lick granuloma
Irregular hyperplasia of the epidermis and follicular infundibula
Compact hyperkeratosis and multifocal parakeratosis
Vertical streaking
27
What is another name for intercellular edema on histopath?
Spongiosis
28
What is another name for intracellular edema on histopath?
Ballooning degeneration
29
What is hydropic degeneration?
Intracellular edema of the BASAL cell layer
30
Where are inclusion bodies found for poxvirus?
Within the cytoplasm
31
Where are inclusion bodies found for herpesvirus?
Within the nucleus
32
What is acanthosis?
Thickening of the epidermis
33
Describe the histopathologic findings of uveodermatologic syndrome
Lichenoid to interface histiocytic dermatitis
Pigmentary incontinence
34
What phase is this hair in?
Telogen (retraction of papilla, trichilemmal keratinization)
35
What glands are highlighted in this image?
Epitrichial (dog paw pad)
36
How could you confirm a vessel is a lymphatic vessel on histopath?
Use LYVE-1 stain
37
What is a unique feature of feline herpesvirus on histopath?
Necrosis of epitrichial sweat glands
38
Where are inclusion bodies found on histopath of FHV?
Intranuclear within keratinocytes/histiocytes
39
Where are inclusion bodies found in distemper virus?
Keratinocyte cytoplasm (intranuclear rare)
40
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?
Dermatophilosis congolensis
41
How could you differentiate a cat with endocrine alopecia from one with paraneoplastic alopecia on histopath?
Paraneoplastic: Follicular and adnexal atrophy + epidermal HYPERPLASIA
Endocrine: Follicular and epidermal ATROPHY
42
What other condition does feline thymoma-associated exfoliative dermatitis resemble on histopath?
Erythema multiforme
43
What is the term for excessive trichilemmal keratinization?
Flame figure
44
Describe the histopathologic findings in SND
Parakeratotic hyperkeratosis (red)
Intra- and intercellular edema (white)
Basal cell hyperplasia (blue)
45
What histochemical stains can be used to highlight mast cells on biopsy?
Giemsa
toludine blue
46
What is the typical description of the basal cell layer in Bowen's disease?
"Wind swept" appearance
47
Describe 2 major histopath findings for SCC
Cords of dysplastic keratinocytes in dermis
Keratin pearls
48
What conditions are associated with keratin pearls on histopath?
SCC
Follicular cyst
IKA
49
What histopathologic feature can help differentiate between plasmacytoma and histiocytoma?
presence of Grenz zone in plasmacytoma
50
What is a Grenz zone?
Narrow area of unaffected dermis seen in some dermal neoplasms (separates unaffected epidermis from affected dermis --> plasmacytomas)
51
You are trying to differentiate between histiocytoma and cutaneous reactive histiocytosis on histopath. How does the distribution of cells help with this?
Histiocytoma: top-heavy (epitheliotropism)
Histiocytosis: Bottom-heavy
52
What marker is lacking in cutaneous reactive histiocytosis that can help differentiate it from a histiocytoma?
E-cadherin
53
Define pagetoid reticulosis
Epitheliotropic lymphoma limited to the epidermis
54
Define mycosis fungoides
Epitheliotropic lymphoma that invades that epidermis, hair follicle, AND dermis
55
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?
Histiocytoma
56
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?
1) Plasmacytoma
2) Non-epitheliotropic lymphoma
57
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?
MCT
CETL
Histiocytic sarcoma
TVT
58
What protein is mutated in canine MCT?
p53
59
What immunohistochemical stains help differentiate histiocytoma from reactive histiocytosis?
Histiocytoma: positive E-cadherin, negative Thy-1 and CD4
60
What is the term for focal accumulations of atypical lymphocytes within the epidermis (i.e. as seen in CETL)?
Pautrier microabscesses
61
What type of tumor has a "picket-fence" configuration of spindle cells abutting the epidermis?
Equine/feline sarcoids
62
What differentiates sebaceous hyperplasia from sebaceous adenoma on histopath?
Sebaceous hyperplasia: retention of normal orientation of seb glands around ducts/follicular infundibulum, no degeneration/dropout of mature sebocytes
63
What feline condition does ECLE resemble on histopath?
Exfoliative dermatitis
64
What condition is associated with Touton cells?
Xanthomas
65
Where are inclusions found in avian poxviruses?
Eosinophilic intracytoplasmic inclusions (Bollinger bodies)
66
What are the top differentials for cytotoxic interface dermatitis?
Cutaneous lupus (any form)
Ischemic dermatopathy
Fixed drug reaction
Lupoid onychitis
Pemphigus erythematosus
VKH
Erythema ab igne
CETL (very rare)
67
What are the top differentials for a panepidermal cytotoxic dermatitis?
EM
SJS
TEN
PNOE
thymoma-associated exfoliative dermatitis
CETL
Staph toxic shock syndrome
68
What part of the body tend to have a lichenoid band with ANY form of inflammatory disease?
MC junctions
69
What are the top differentials for lichenoid inflammation WITHOUT cytotoxic changes?
Any mucocutaneous junction inflammatory disease (including MCP)
Psoriasiform-lichenoid dermatitis
70
What type of follicular tumor has a medusoid pattern?
Trichoblastoma (these tumors are not typically cystic)
71
What breeds are predisposed to IKAs?
Norwegian Elkhounds
GSDs
72
What follicular tumor is characterized by "ghost cells"?
Pilomatricoma
73
What type of follicular tumor is more likely to have mineralization: pilomatricoma or trichoepithelioma?
Pilomatricoma (very uncommon to see mineralization in trichoepitheliomas)
74
True or false: Bowenoid in situ carcinoma can be solar induced
False - Bowenoid implies it is VIRAL-induced
75
What are the clinical characteristics of Bowenoid in situ carcinomas?
Fully haired areas
Multicentric
(Bowenoid carcinomas are NOT solar-induced carcinomas)
76
In what condition might you find fine pigment dusting within macrophages?
VKH
77
You find the highlighted area on histopath from a neoplastic region. What is the feature and what is this most consistent with?
Keratin pearl-- SCC
78
There is a "swarm of bees" pattern surrounding the inferior segment of an anagen follicle. What is the likely diagnosis?
Alopecia areata
79
What is being demonstrated by the red line in this image?
Transepidermal elimination
80
What is the term used for inflammation in apocrine glands?
Hidradenitis
81
What histologic stains can be used to highlight mucin?
Mucicarmine
Alcian blue
Ferric iron
Muscarinic acid
82
What is highlighted in the circled areas?
Colonies of coccoid bacteria
83
You obtain this histology from a dog with a facial-predominant crusting dermatosis. What is the most likely diagnosis?
Zinc-responsive dermatosis
84
What is the most likely breed for this biopsy?
Shar Pei (Shar Pei mucinosis)
85
What histopathologic features are consistent with a facial origin?
Increased # of sebaceous glands
Sinus hairs
Possible skeletal muscle present
86
What is highlighted by the red line and what is the most likely diagnosis?
Pautrier's microabscesses (intraepidermal lymphocytic aggregates)
CETL
87
What is being demonstrated by the circled area in this photo?
Variably sized keratohyalin granules (think viral)
88
What are the structures highlighted in this photo?
Koilocytes
89
What is being demonstrated in this photo and what is the likely cause?
Intranuclear inclusion body
Likely viral infection
90
What is a cevatte body?
An apoptotic keratinocyte present in the basal cell layer of the epidermis
91
What species did this likely come from?
Horse (eccrine glands)
92
What part of the body did this likely come from?
MC junction (skeletal muscle, few HF, deep rete ridges, thick epidermis)
93
What condition is consistent with parakeratotic capping and papillary squirting?
ZRD
94
You find the following on histopathology from a nodule on a dog trunk. What is the diagnosis?
MCT
95
Where on the body did this biopsy likely come from?
Paw pad (non-haired skin, hyperkeratosis, adipose tissue, presence of eccrine sweat glands would also help)
96
Are the melanin changes in this biopsy normal or abnormal and why?
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
What special stain is this and what is it highlighting?
GMS -- elastin
98
This biopsy is from a cat. What stain was likely used and what is the most likely diagnosis?
Fites stain- mycobacteria
99
In what part of the tissue should you look if you are trying to diagnose Mycobacteria in a cat?
SQ fat
100
This biopsy came from a dog pinna. What is the likely diagnosis?
Leproid granuloma (Fites/Ziehl Nielson stain)
101
What species did this biopsy likely come from?
Horse (abundant sebaceous gland, simple HF)
102
This biopsy came from a cat. What is the highlighted cell and what is the most likely diagnosis?
Mott cell (plasma cell filled with Ig)
Plasma cell pododermatitis
103
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?
PCR of LN/bone marrow (this is likely Leishmania -- image shows macs filled with granular material which is the kinetoplasts)
104
A cat is presented with draining tracts, fever, and lameness. What is the most likely diagnosis based on this image?
Coccidiodomycosis (endosporulation apparent, diagnostic feature of Coccidiodomycosis)
105
You find the circled organism on histopath. What is the most likely diagnosis?
Prototheca (internal septations)
106
You see the following changes on histopathology. What stain could be applied to highlight the suspected cause?
Mucicarmine (stains cryptococcus capsule)
