Path Flashcards

(201 cards)

1
Q

Stains for Langerhans cell histiocytosis

A

S100, CD1a and Langerin CD207

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2
Q

Elastin stains

A

Verhoeff van Gieson

Weigarts

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3
Q

Acantholysis and dyskeratosis - differentials?

A
Hailey hailey
Darier
Grovers
Warty dyskeratoma
Acanthokytic acanthoma
Familial dyskeratotic comedones
Acantholyitc Ak
Acantholytic SCC
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4
Q

Small blue cell tumours

A
LEMONS
Lymphoma
Ewing sarcoma
Merkel cell cancer/melanoma
Oat cell cancer of the lung
Neuroblastoma
Small cell endocrine cancer
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5
Q

Spindle cell tumours

A
SLAMDUNKB
SCC
Leiomyomas
Angiosarcomas
Melanoma/merkel cell cancer
DFSP
Undifferentiated pleomorphic sarcoma
Neurofibroma
Kaposi's Sarcoma
\+ BCC
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6
Q

Lymphatic stain

A

D240

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7
Q

Types of multinucleated giant cells

A

Langhans cells - circular
Touton - circular with foamy centre
Foreign body - macrophages all together

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8
Q

Grenz Zone

A
Granuloma faciale
Lymphoma cutis
Pseudolymphoma
B cell lymphoma
Lepromatous leprosy
Acrodermatitis chronica atrophans
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9
Q

Cornoid lamella histology

A

Column of parakeratosis with dyskeratosis underneath

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10
Q

Spindle cell tumour differential and the stains that go with it

A

SLAMDUNK
SCC - CK903 and HMW keratin
Leiomyosarcoma - Desmin and SMA
Angiosarcoma - CD31 and CD34
Melanoma - S100 and MART-1
DFSP - CD34, negative for factor 13a and stromelysin
Undifferentiated pleomorphic sarcoma and AFX - CD68, CD10 and procollagen
Nodular fasciitis - HSP47, actin
Kaposi’s sarcoma - CD31, CD34, HHV-8 (Lana)

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11
Q

Acanthosis definition

A

Thickening of the epidermis

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12
Q

Types of giant cells

A

Langhans - horseshoe shape
Foreign body - nuclei dispersed more evenly
Touton - foamy cytoplasm with circular nuclei around non-foamy core

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13
Q

Merkel cell stains

A

CK20, neuron-speciifc enolase, TTF1 negative

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14
Q

Merkel cell appearance

A

Large, oval violet-blue cells that appear smudgy

Normally seen at base of rete ridges

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15
Q

Histiocyte appearance

A

Large, vacuolated nucleus

Develop into macrophage (CD-68) or dendritic, Langerhans cell

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16
Q

Nerve stain

A

S100, Bodian

Negative for Bodian with neurofibroma

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17
Q

T cell stain

A

CD3

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18
Q

Mononuclear cell stain

A

CD6

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19
Q

B cell stain

A

CD20

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20
Q

NK cell stain

A

CD56

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21
Q

Macrophage stain

A

CD68, lysozyme

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22
Q

Mast cell stain

A

CD117

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23
Q

Dermal dendrocyte staine

A

Factor 13a

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24
Q

Indeterminate cell stain

A

S100, CD1a, but no Birbeck granules

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25
Pit rosea histology
Undulating epidermis with focal parakeratosis and spongiosis - may resemble small Pautrier microabscess Lymphocyte exocytosis Perivascular infiltrate Extravasasted RBCs
26
Alcian blue
Blue; common mucin stain
27
Congo red
Red; typical for staining amyloid fibres
28
Crystal violet
Violet; can stain glia and neurons
29
Fontana-Masson
Black/pink or red; stains melanin
30
Luna stain
Purple/black; can stain mast cells and elastin
31
Nissl stain
Blue; stains the rough endoplasmic reticulum in neurons
32
Period Acid Schiff
Red/magenta; used to stain glycogen, basement membranes, reticular fibres, cartilage, glycoproteins, glycolipids and mucins in tissues.
33
Red Oil 3 stain
Red; used to stain fat emboli
34
Reticulin stain
Blue/black; stains reticular fibres
35
Sudan black stain
Brown-black; stains myelin tissue
36
Toulodine blue
Blue; stains mast cell granules
37
Van Gieson stain
Red/blue/yellow; used to study blood vessels and skin, can stain collagen, nucleus, red blood cells, cytoplasm
38
What is immunohistochemistry
HC uses primary antibodies to label a protein, then uses a secondary antibody which is bound to the primary one. In immunoperoxidase staining, an antibody is joined to an enzyme, peroxidase, that catalyses a reaction in which the protein is specifically stained brown. IHC can also involve fluorescently labelled antibody so that when viewed under a light microscope a certain pattern will be observed from the emitted fluorescence.
39
BCL2 stain
Used to distinguish between basal cell carcinomas and trichoepitheliomas
40
CD3 stain
T-cell marker; strongly positive in mycosis fungoides
41
CD4 stain
Helper T-cell marker
42
CD8 stain
Suppressor T-cell marker
43
CD20 stain
B-cell marker
44
CD30 stain
Can be used in the diagnosis of Hodgkin lymphoma and anaplastic lymphomas. Large cells: Golgi apparatus and membranous staining
45
CD31 stain
Helps to identify endothelial tumour
46
CD34 stain
Distinguishes different endothelial tumours and is positive in dermatofibrosarcoma
47
CD56 stain
Used in the diagnosis of non-Hodgkin lymphomas, leukaemias and small cell carcinomas
48
CD117 stain
Marker for KIT receptor and positive in various tumours including mastocytosis
49
CDKN2A (p16)
Tumour suppressor marker positive in HPV-associated tumours, actinic keratoses and squamous cell carcinoma
50
CK stain
Cytokeratins can be used to help distinguish benign from malignant adnexal tumours
51
CK20 stain
Specific for Merkel cell carcinoma. Can help identify adenocarcinomas of the gastrointestinal and reproductive system as well as gastrointestinal epithelial tumours
52
Cytokeratin High molecular weight
Used to detect ductal carcinomas, squamous cell carcinomas and other epithelial neoplasms
53
Desmin stain
Muscle marker
54
EMA stain
Used to identify eccrine neoplasms, Paget disease and sebaceous carcinomas
55
Factor 13 stain
Can help clinicians distinguish between dermatofibrosarcoma and dermatofibroma
56
HMB45 stain
Used to detect melanocytes, especially in melanoma but negative in desmoplastic melanoma
57
Melan-a stain
Can help identify melanocytic naevus cells and melanomas
58
S100 stain
Used to mark tumours of the melanocytes, both naevi and melanoma
59
SMA stain
Smooth muscle antigen
60
SOX-10 stain
Nuclear marker for melanocytic tumours
61
I want to find mucin - what should I stain?
PAS (periodic acid Schiff) for neutral mucin Alcian Blue for acid mucin Mucicarmine
62
I want to find melanin - stain?
Fontana-Masson
63
I want to find iron - stain?
Perl's Prussian Blue
64
I want to find calcium - stain?
Von Kossa | Alizarin red
65
I want to find fibrin - stain?
MSB (Martius Scarlet Blue)
66
I want to find elastic fibres - stain?
EVG (Elastic Van Geisen) for reticular dermis | Orcein for papillary dermis
67
I want to find fat - stain?
Oil Red-O (Fat is dissolved in tissue processing, frozen section required)
68
I want to find mast cells - stain?
Toluidine Blue | Giemsa
69
I want to show bacteria - stain?
Gram (gram-negative organisms are very difficult to demonstrate) Ziehl-Neilson for most mycobacteria (ZN for AFB) Wade-Fite for M. Leprae
70
I want to show fungi - stain?
PAS | Grocott / Gomori methenamine silver (GMS)
71
B cell markers
CD20 and CD79a
72
Most mature lymphocytes markers
Leukocyte common antigen
73
I want to find macrophages, stain?
CD68
74
Jigsaw puzzle like histo structure
Cylindroma Thickened basement membrane material Elongated duct like spaces These are apocrine
75
Where do you find squamous eddies
HPV
76
Schwanomma histo
- Encapsulated, well-circumscribed lesion beneath uninterrupted epidermis - Antoni A: more cellular -> composed of haphazard arrangement of bland cells with spindled and oval nuclei - Antoni B: lose, less cellular areas, with loose oedematous and mucinous stroma with fibrillar collagen. Vessels are prominent and often surrounded by dense sclerosis - Verocay bodies: parallel columns of elongated nuclei either side of homogenous acellular material - Positive for S100
77
Schwanomma ddx
- Neurofibroma: won't be encapsulated - Plexiform neurofibroma -> have nerves coursing through the mass - Perineuroma: stains positive for EMA and S100 - DFSP: CD 34 positive, S100 negative and lacks Antoni A and Antoni B pattern of schwannoma
78
Angiosarcoma stains
CD31 and CD34
79
Scabies histology
Pig tail sign Lymphocytes, histiocytes, eosinophils Lymphoid aggregates
80
Tick bite histology - which cells more?
Neutrophils
81
Intra cytoplasmic inclusion bodies are seen in what
Melanocytes | Adipocytes
82
Mitotic stain
PHH3
83
Proliferation marker
P67
84
What is histiocytic sweets associated with
More Haem malignancy
85
Mast cell stain
Leider- goes red
86
Bed bug Latin name
Cimex lectularis
87
Differentials for subcorneal pustules
``` Candida, tinea Pustular psoriasis Subcorneal pustular dermatosis IgA pemphigus/IgG pemphigus Pyoderma vegetans ```
88
Types of tattoo reactions
Sarcoidal (granulomatous) Hypersensitive Infectious --> suppurative
89
Epithelioid granuloma differentials
TB/Leprosy | Sarcoidosis --> 25% of granulomas can be perineural
90
Investigations that you would do for someone with erythema induratum
CXR, Quant Gold, Tuberculin skin test? | Ziehl Neelson stain, Mycoplasma PCR
91
Types of histologic GA
Perforating Interstitial Necrobiotic Sarcoidal
92
Epithelioid cell tumour ddx
``` SCC Melanoma AFX - more spindly Histiocytes Lymphomas - CD34 Angiosarcoma ```
93
Syphilis stain
Warthin starry
94
How do you distinguish eccrine from apocrine
Apocrine stains CD15 | Apocrine has snouting /decapitation
95
Cells with grooves in them
Langerhans | T lymphocytes
96
Pagetoid spread
``` Paget’s disease Melanoma Bowen’s Sebaceous carcinoma Histocytosis ```
97
Melanoma stains
S100, SOX10, Melan-A, HMB45, PRAIME - latter good for margin control, but is an evolving subject
98
Granular cell tumour
Nodule - blue cells: large cytoplasm with granules, S100 positive. Rare. Occurs in the subcutaneous tissue in 30-40%, nearly 25% in the tongue. 1-3 cm, painless. 98% benign, malignant change rarely can occur
99
Test for coeliac in DH
Transglutaminase IgA Anti-endomyosin antibodies Gliadin
100
Neural stains
s100 and SOX 10
101
Myocytes
Spindle cells | brightly eosinophilic cytoplasm, blunt-ended, cigar-shaped nuclei
102
Iron stain
Pearl stain
103
What condition is sclerotic fibroma associated with
Cowdens
104
What colour does colloidal iron stain and what does it stain
Blue | Mucin
105
Mast cell stain
Toluidine blue | Giemsa
106
What antibody can you do to distinguish ulcerative colitis and Crohn’s disease?
anti-Saccharomyces cerevisiae antibodies
107
BCC stain
BerEP4 MOC31 Can be positive in adnexal tumours
108
Low molecular weight cytokeratins
Cytokeratin 7 and 19 - positive in BCC, negative SCC, can be positive in adnexal If the SCC has arisen from Bowen’s it can be cytokeratin 7 positive Cytokeratin 20 is also a LMW
109
High molecular weight cytokeratins
CK 5/6 CK 34 beta E 12 Can be positive in BCC, always positive in SCC, and almost invariably positive in adnexal tumors
110
SOX10 for adnexal neoplasms
Negative in BCC and SCC but can be positive in adnexal tumours and is a good way to differentiate
111
GCDF15
Negative in BCC and SCC, can be positive in adnexal
112
Pagets staining
CEA cytokeratin 20 | Can use GCDF 15
113
Schmorl stain
Reduces properties of melanin to stain granules blue green | Easier than Fontana Mason
114
Urticarial dermatitis- how is it different to urticaria
Has urticaria and eczema overlap The more eos the more you need to think of BP Biopsy: dermal dermatitis with mixed inflammatory cells in the dermis and minimal spongiosis in the epidermis
115
What day should you do hormonal testing of the menstrual cycle
Day 5-7
116
Granular cell tumour stains
S100 PGP9.5 - Neuron specific peptide Neuron specific enolase Nerve growth factor receptor Can have histiocytic markers: CD68, NKI/C3 Can have markers of melanocytic differentiation: MITF SOX10 True neural granular cell tumours have all of the above, non neural are the histiocytic markers (congenital granular cell tumour)
117
Perineuroma stains
EMA Claudin 1 Type IV collagen Laminin
118
Differentiation of malignant peripheral nerve sheath tumour from soft tissue sarcomas
Lacks H3K27me3- trimethylation of lysine 27 on his tone H3 which repress transcription In about 80% of cases it lacks it
119
Virus associated with Merkel cell carcinoma
Polyomavirus in 80%
120
Merkel cell carcinoma stains
CK20, CK5/6, CK7 - corresponds to the ultrastructural distribution of paranuclear whorls of intermediate filaments Positive staining for various neuro endocrine markers: chromogranin, synaptophysin, somatostatin, calcitonin, vasoactive intestinal peptide Neuron specific enolase, occasionally neural filaments, CD56 S100 negative Thyroid transcription factor 1 negative (helps differentiate from from cutaneous metastasis) Could also do polyomavirus P63 may indicate more aggressive behaviour
121
Path for infantile haemangioma- stains
``` GLUT1 Lewis Y antigen Meridian Fcgamma RIO Wilms tumour protein ```
122
What is satellite necrosis
Lots of lymphocytes around a single cell
123
Alopecia areata path
Increased telogen count Swarm of bees Eos Pigment casts
124
Mycobacterium stain
Wade Fite Ziel Nielson Gram Silver
125
Dendritic stain
Factor 13a
126
Types of granulomas
``` Necrobiotic Sarcoidal Tuberculoid Foreign body Suppurative ```
127
Difference between sebaceous hyperplasia and adenoma
Hyperplasia not connected to epidermis | Adenoma is
128
Which part of the hair follicle has a granular layer
Infundibular
129
Spirochete stain sensitivity
60-90%, but not helpful if it’s alopecia
130
Difference between GA and IGD
GA has collagen trapping and mucin
131
If sebaceous adenoma is positive for all MTS stains, what is risk of MTS
5%
132
Stains for liposarcoma
MDM2, CDK4, adipophilin, p16 | CD10 in ~20%
133
Stains for leiomyoma
SMA and desmin | Then can do HLRCC: fumarate hydratase to look for Reed syndrome
134
Stains for leiomyosarcoma
actin, dermin, h-caldesmon, CD10 | usually negative but can be positive: cytokeratin, S100 -
135
stain to differentiate apocrine and eccrine
CD15 positive in apocrine not eccrine
136
sebaceous glands - different names for different locations
- Fordyce spots or granules: vermillion lip and oral mucosa - Meibomian glands: eyelids - Montgomery tubercles: areolae - Tyson glands: labia minora and prepuce
137
Muir Torre stains
MSH 2 MSH 6 MLH 1 PMS 2 If MSH 2 is negative - then more likely to have MTS So looking for loss of these - they are micro stability arrays
138
Stains for amyloid
Crystal violet better | Congo red - shows apple green
139
Muir Torre Syndrome stains
MSH 6 MSH 2 MLH1 PMS2
140
Stain that is positive for AFX
CD10
141
Masson trichome stain
Collagen: blue or green Keratin and muscle: fiber Bone: light red or pink
142
Glomus cell stains
SMA and actin Myosin may be positive CD 34 and 31 negative
143
Ddx for perivascular lymphocytic infiltrate
``` 7 Ls: Lupus PMLE Lymphoma Pseudolymphoma Jessners Lues Leprosy ```
144
What are the features of HSV
Multinucleating Marginación of chromatin Molding of nuclei Ballooning degeneration
145
Ways to identify amyloid
Crystal violet metachromasia Positive staining with alkaline Congo red Apple green birefringence under polarised light after Congo red staining Thioflavin T staining: brightly by UV fluorescence microscopy Antibodies to amyloid P Stain against specific precursors like keratin
146
What is particular about ERPHB4 mutation
It’s an AVM mutation that’s more likely to have neuro involvement
147
How to tell if urate/gout
20% silver nitrate - crystals appear bland and surrounding tissue yellow De Galantha stain - crystals brown black (normal tissue yellow) Polarized light: brightly refractile brown sheaths of fine needle-like crystals can be seen
148
How is pseudogout different to gout
CPPD crystals are shorter than urate, and rhomboidal in shape Tophaceous pseudogout: rhomboid crystals as well as foci of calcification are seen within the dermis Stain with non-aqueous alcoholic eosin stain --> CPPD crystals with positive birefringence, as opposed to negative birefringence in gout and tumoral calcinosis
149
Stain for leishmaniasis
Giemsa | ?CD1a
150
Stains to do for xanthomas
Oil red O - red Scarlet red - red-brown Schultz- cholesterol and cholesterol esters are blue green, positive in xanthomas except eruptive And IHC CD68
151
Gout tophi stains
Von Kossa De Galantha more specific for urates Negative birefringence with polarized light
152
Gouty tophi histo
If formalin fixed: amorphous eosinophilic deposits in dermis and s/c tissue Alcohol fixed: brown, needle shaped crystals
153
Stains for glomovenous malformation and glomus
SMA Vimentin CD34
154
Stains for neurofibroma
S100, C34, PGP9.5, factor 13a, myelin basic protein, neurofilaments Bodian stain rarely performed - reveals axons
155
Stains for schwanomma
``` S100 Vimentin Sox 10 MBP Neurofilament is negative ```
156
Trichome stain
collagen is stained blue, nuclei are stained dark brown, muscle tissue is stained red, and cytoplasm is stained pink
157
DFSP histopathology findings
Spindle cells in deep dermis and subcutaneous fat Form herring bone or honeycomb or storiform pattern Spindled or wavy nuclei Pigmented variant: Bednar tumour CD34 positive, Factor 13a negative, stromelysin 3 negative
158
DF histology findings
Lobular Acanthosis with hyperpigmented basal layer (dirty feet) Collagen trapping Variable mixture of spindle fibroblasts and histiocytes (can be xanthomatous) F13a positive, CD34 negative
159
IHC for CBCL
CD20, CD 79a Follicular: Cd10 positive, BCL-2 negative Leg type: BCL-2 positive (marginal zone also BCL-2 positive) Exclude systemic: MUM-1, CD5, CD23
160
Main CBCL histo features
Grenz zone Follicular: 25% follicular, 75% diffuse, has centrocytes and centroblasts. Positive CD10 (sometimes), CD20, 79a, negative BCL-2, MUM-1, CD5, CD23 Marginal zone: marginal zone cells (pale), plasma cells, eos, Dutcher bodies
161
Eosinophilic spongiosis ddx
BAD Bite/ Bullous (PV/PF, BP/PG,MMP, EBA) ACD /AD Drug eruption Other: Well’s, MF, PEP, IP, Erythema toxicum Neonatorum
162
Dermal eosinophilia ddx
Dermal eosinophilia ddx BAD - FUGUE (No vasculitis) Bite/ BP (BP/PG,MMP, EBA) ACD/AD Drug eruption ``` Fungal inf (+Neut) Urticaria (+Neut & edema) GF (+Neut), Eos Granuloma (+ LCH) Unknown? Dermal HSR Eos folliculitis Eos Cellulitis (WELLS) ``` Ps: Angiolymphoid hyperplasia with eosinophilia (if +VESSELS & Plump endothelial cells)
163
Ddx for pale cells in epidermis
Sharp migration of pale cells: ``` Syphilis Hartnup Acrodermatitis enteropathica Radiodermatitis Pellagra, psoriasis Necrolytic migratory erythema Pagets Clear cell acanthoma, papulosis, SCC ```
164
Ddx of clear cell dermal tumours
``` Sebaceous adenoma/carcinoma Trichilemmoma/cyst Pilomatricoma Clear cell acanthoma/BCC/scc/hidradenoma/syringoma Pagets ```
165
Main ddx for foam cells
``` Histiocytoses: JXG, NXG, LCH Xanthomas Sebaceous tumours AFX Leprosy ```
166
Perniosis histo features
``` Minimal epidermal change Peri-v lymphocytic, can get lymphocytic vasculitis - sup and deep Dermal oedema RCC extravasation Very dermal ```
167
EM histo features
``` Basketweave stratum corneum (acute) Lichenoid/interface Civatte bodies Mild epidermal spongiosis Dermal oedema Lymphs and eos (latter can be sparse) DIF: non specific, granular deposits of IgM and C3 around BV and at DEJ ```
168
How is FDE different to EM
Melanophages More neuts and eos Lymphocyte exocytosis May have papillary dermal fibrosis
169
Granular parakeratosis histology
Thickened parakeratosis with retention of keratohyaline granules Thickened eosinophilic stratum corneum
170
Difference between photoallergic and phototoxic
Photoallergic is more eosinophilic | Phototoxic is more neutrophilic
171
How are the physical urticarias different to normal urticaria
Have more neutrophils
172
Stains to do for suppurative granuloma and infections
Gram (Brown–Brenn) Bacterial infections Periodic acid Schiff (PAS) (Fungal cell walls Black/Mycotic infections) Grocott (GMS) methenamine silver (Fungal cell walls Black/Mycotic infections)- Black Ziehl–Neelsen  Mycobacterial infections Wade-Fite Mycobacterium TB/ leprae/ MOTT (mycobacteria other than tuberculosis) Warthin–Starry? Spirochetes (Syphilis), Granuloma inguinale (Donovanosis) , Rhinoscleroma, Bacillary angiomatosis Giemsa?  leishmania
173
Rheumatoid nodule histology and stains
Large irregular granulomas with central necrobiosis (palisading macrophages) Appear pink in nature This is from fibrin --> stain positive for Martius Scarlet Blue Will be negative for mucin
174
Actinic granuloma histology
``` Solar elastosis Elastophagocytosis Diffuse granulomatous infiltrate Reduction in elastin (van Gieson - stains elastin black) No mucin No necrobiosis ```
175
Koilocyte
Raisin like nuclei with halo
176
Two main strains of HPV that cause cutaneous warts
6 and 11
177
HSV and VZV findings on histology
Epidermal spongiosis Intra-epidermal vesiculation Pale keratinocytes Acantholysis Keratinocytes have viral changes: molding, margination, multinucleate, pale grey, enlarged Intra-nuclear eosinophilic inclusions: Cowdry type A or Lipschutz bodies Peri-v lymphs and neuts - sometimes vasculitis
178
Suggestions of fungal infection on histo
``` Sandwich sign: alternating ortho and parakeratosis with basketweave stratum corneum Neutrophils in the stratum corneum Septate hyphae Can be an invisible dermatosis Spongiosis, peri-follicular neutrophils ```
179
Cryptococcus stains
Central: PAS, methenamine silver, Fontana Masson Capsule: alcian blue, mucinarme, Indian ink
180
Leishmaniasis stain
Giemsa
181
Donavonosis stains
Warthin starry Leishman Giemsa Looking for parasitzed macrophages (Donovan bodies)
182
Touton giant cell ddx
JXG NXG Dermatofibroma Sometimes xanthomas
183
JXG stains
CD68 +ve, Factor 13+ve CD1a and Langerin –ve 10% other cells in lesion S100 +ve
184
LCH histology
Diffuse dermal infiltrate of Large histocytes with with indented or RENIFORM (“coffee-bean” or Kidney shape) nucleus and abundant eos cytoplasm Often mixed with various inflammatory cells lymph + Eos (esp if eosinophilic granuloma Eos +++) epidermotropism also seen (which differs from mastocytosis) EM = Birbeck granules (“tennis racquet”) within cells Positive  CD1a, S100, Langerin (CD207) Negative CD68, factor XIIIa
185
Xanthoma histology
Foamy histiocytes (rarely touton giant cell) older lesions have cholesterol clefts neuts in young lesions, particularly eruptive Stain positive for: Oil Red O (cholesterol goes red) , Scarlet Red (goes red), Schultz (goes blue-green) CD68 positive
186
Amyloidosis stains and colours
Crystal violet -> metachromatic Congo red --> apple green birefringence Pagoda red --> specific to amyloid, will be negative for colloid milium Thoflavin T --> green-yellow
187
Colloid milium stain
Van Gieson stains black
188
Gout histology
Granulomatous reaction with macrophages and foreign body giant cells acellular bluish material in dermis; negative birefringence with polarized light (unlike pseudogout) Formalin-fixed = amorphous, eosinophilic deposits in dermis and subcutaneous tissue (crystals dissolved) Alcohol-fixed = brown, needle-shaped crystals (doubly refractile) Positive staining with von Kossa, but de Galantha is more specific for urates
189
Stains to do in hypertrophic scar
Van Gieson - loss of elastin
190
Difference between keloid and hypertrophic
Keloid has more mucin, no epidermal involvement, decreased vascularity, no incr in fibroblasts Hypertrophic: has vertically oriented capillaries, epidermal involvement, no incr in mucin, parallel oriented collagen and fibroblasts
191
PXE histology
``` Bx from (affected or normal skin): “Purple-squiggles” or “bramble-bush” disease Fragmented, short, basophilic, calcified elastic tissue fibers in mid-dermis (only elastic disorder you can see with only H & E stain) calcifications -> Calcium salts are deposited on the abnormal elastic fibers (do not confuse with calcinosis cutis) von Kossa method stains calcified elastic fibers black and VVG stains elastic fibers ```
192
KHE genetic mutation
GNA14
193
Stains for KHE
CD31, CD34, podoplanin (lymphatic endothelial), LYVE-1, VEGFR-3, Prox1, D240 ? latter from NSS
194
Ix to do for KHE
MRI (enhances on T2 hyperintense, ill-defined margin that crosses tissue planes), FBC, coagulation studies, platelets, fibrinogen degradation products, biopsy for histopath if safe to do so
195
AFX stains
CD10 and CD99
196
Proliferation marker
Ki67
197
Cytotoxic T cell markers
Perforin Granzyme TIA-1
198
Marker of systemic lymphoma
ALK-1
199
Bowens disease main path features
``` Parakeratosis/orthokeratosis Loss of granular layer Full thickness atypia Eyeliner sign +/- clear cell change, +/- acantholysis Loss of maturation ```
200
Mucocele stains
Sialomucin is positive for PAS and mucopolysaccharide | And then Alcian blue or colloidal iron
201
Digital mucous cyst histopathology
Acral skin well-circumscribed dermal accumulation of mucin + stellate fibroblasts Pseudowall is made of dense fibrous tissue Collarette of epidermal RR may clutch the mucin Not considered a true cyst Can have epidermal collarette trying to embrace mucin