Ch. 1 - IHC Flashcards

1
Q

What enzyme reaction forms the basis of IHC?

A

Diaminobenzidine method (DAB): Visualizes presence of enzyme-antibody-antigen complex fixed to tissue as a stable brown product. 3-amino-9-ethylcarbazole (AEC) can be used for red staining (does not archive as well).

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2
Q

CK polyclonal keratin (pankeratin)

A

Polyclonal cocktail that offers greater sensitivity than AE1/AE3.

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3
Q

p63

A

Expressed in basal and spinous cells of epidermis, germinative cells of sebaceous glands, and myoepithelial cells of sweat glands.

Useful in distinguishing cutaneous origin of spindle cell neoplasms.

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4
Q

CK7

A

In general, a marker of non-GI adenocarcinomas. Also marks Paget’s.

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5
Q

CK20

A

Marker of GI adenocarcinoma and merkel cell carcinoma (paranuclear dotting).

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6
Q

AE1/AE3

A

High and low weight keratins. Stains all epithelial tumors as well as epithelioid sarcoma, synovial sarcoma, and mesothelioma.

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7
Q

CAM5.2

A

Detects LWMK of glandular neoplasms but not epidermis. Marks Paget’s.

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8
Q

CDX2

A

Marker of intestinal adenocarcinoma (usually metastatic CRC)

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9
Q

EMA

A

Highlights normal sebaceous and sweat glands. Positive in sebaceous, squamous cell carcinomas and Paget’s. Negative in BCC.

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10
Q

CEA

A

Marks sweat glands. Positive in most adenocarcinomas…

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11
Q

Adipophilin

A

Expressed in lipid droplets of sebaceous and xanthomatous lesions.

Can distinguish sebaceous carcinoma from SqCC/BCC

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12
Q

Ber-EP4

A

Marks epithelia except those undergoing squamous differentiation.

Positive in BCC, not SqCC.

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13
Q

Desmin

SMA

A

Desmin: Stains skeletal and most smooth muscle (not vascular smooth muscle)

SMA: Stains smooth muscle, including vascular smooth muscle (and glomus cells)

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14
Q

CD34

A

Marker of vascular endothelium and hematopoietic progenitor cells.

Positive in DFSP but not DF. Positive in spindle cell, sclerotic fibroma, SFT, and many others.

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15
Q

Factor XIIIa

A

Highlights dermal dendritic cells.

Positive in DF but not DFSP. Positive in fibrous papule of the face.

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16
Q

CD31

A

More specific vascular marker than CD34

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17
Q

D2-40 (podoplanin)

A

Lymphatic endothelial marker.

For detecting LVI and mets (nonreactive vs primary)

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18
Q

UEA (Ulex europeus agglutinin)

A

Binds vascular endothelium

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19
Q

GLUT1 (glucose transporter)

A

Expressed in endothelial cells with blood-tissue barrier function.

Positive in infantile hemangiomas (but not AVMs), also stains perineural cells.

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20
Q

Vimentin

A

Stains almost everything but epithelium.

General marker of sarcomas and excludes most carcinomas (except synovial sarcoma and rare spindle cell carcinomas)

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21
Q

S100

A

Neural-crest and some mesenchymal lines. Melanocytes, langerhans cells, sweat glands, neural tissue, myoepithelial cells…

Useful in ddx of spindle cell neoplasms

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22
Q

S100A6

A

Stains melanocytes, schwann cells, langerhans cells, and dermal dendrocytes.

Reactive in atypical fibroxanthomas and many other cutanoeus spindle cel neoplasms.

23
Q

HMB-45

A

Premelanosome marker. Lost with normal descent & maturation into the dermis.

Lost in blue nevi. Does not stain desmoplastic melanoma reliably.

24
Q

Melan-A, Mart-1

A

Stains same epitope in melanocytic lesions.

Does not stain desmoplastic melanoma reliably.

25
Q

p75 (nerve growth factor receptor)

A

Early NC marker, expressed in type C (spindled) melanocytes and schwann cells.

Sensitive marker for spindle cell and desmoplastic melanoma.

26
Q

MITF

A

Nuclear melanocytic marker, also positive in cellular neurothekomas.

27
Q

Sox-10

A

Nuclear marker of schwann cells and melanocytes. Sensitive marker of melanoma (all types).

28
Q

Neuron-specific enolase

A

Positive in neuroendocrine cells, neurons, and many other tumors… “non-specific enolase”

29
Q

Synaptophysin / Chromogranin

A

Positive in neuroendocrine cells and merkel cell carcinoma.

30
Q

CD45Ra (LCA)

CD45Ro (UCHL-1)

A

Leukocyte common antigen: General marker of hematolmphoid differentiation, including precursors

UCHL-1: Mature T-cells

31
Q

CD20

A

B-cell antigen (often lost in plasma cells).

32
Q

CD10 (CALLA)

A

Common acute lymphoblastic leukemia antigen: Early B-cell marker.

For B-cell neoplasms, periadnexal mesenchymal cells, atypical fibroxanthomas, renal cell carcinoma, many others.

33
Q

CD79a

A

Plasma and B-cell marker

34
Q

CD139 (syndecan-1)

A

Plasma cell marker

35
Q

CD3

CD4

CD8

A

Pan-T-cell marker.

T-helper marker

Cytotoxic T-cell marker.

36
Q

CD5

A

Pan-T-cell marker like CD3, but aberrant loss in CTCL is common.

Also positive in mantle cell lymphoma and CLL.

37
Q

CD30 (Ki-1, BERH2)

A

Marks Reed-sternberg cells, activated lymphocytes of ALCA and lymphomatoid papulosis.

Also positive in scabies and chronic tick bites?

38
Q

CD7

A

Immature T-lymphocyte antigen, most commonly lost antigen in T-cell lymphomas.

39
Q

CD56

A

Marker of NK cells. Stains blastic plasmacytoid dendritic cell neoplasm (blastic NK/T-cell lymphoma).

40
Q

CD68 (KP1)

A

Reactive in virtually all monocyte/macrophage cells.

41
Q

CD163

A

Reactive in monocytes and macrophages

42
Q

CD123

A

Marker of plastmacytoid dendritic cells (positive in blastic plasmacytoid dendritic cell neoplasm)

43
Q

Myeloperoxidase

A

Granules of neutrophilic myeloid cells. Marker for AML

44
Q

ALK-1

A

Anaplastic lymphoma kinase: t(2;5) in most ALCAs except for primary cutaneous ones. Negative is poor…

45
Q

CD117 (c-Kit)

A

Expressed in mast cells nad melanocytes.

Decrease in nevi and primary melanoma in the dermis. Altogether lost in metastasis.

46
Q

Langerin (CD207)

A

Surrogate marker for presence of Birbeck granules in Langerhans cells.

47
Q

CD43 (Leu-22)

A

Pan-T-cell marker.

Aberrant co-expression with CD20 strongly suggests B-cell lymphoma.

48
Q

BCL2

A

Anti-apoptotic oncogene usually for B-cell neoplasms.

Also stains BCC (entirely) and trichoepitheliomas (outermost layers).

49
Q

MUM-1

A

Expressed in plasma cells, activated T-cells, and some germinal-center cells.

Also expressed in melanocytes.

50
Q

CD21 / CD23

A

Follicular dendritic cell marker.

Residual follicle in lymphoma.

51
Q

BetaF1

A

Identifies alpha/beta T-cells?

52
Q

Ki-67

A

Non-specific nuclear proliferation marker expressed in all phases of the cell cycle.

53
Q

pHH3

A

Mitotic marker that only stains M-phase cells.