IHC

Question 1

Perineurioma

Answer 1

EMA(+), claudin-1 (+), GLUT-1(+)
Variable CD34(+)
Negative for S100 protein, keratin, SMA, desmin, MUC4

Question 2

MPNST

Answer 2

S100 and SOX10 (but both only partial +, never diffuse, both may be -ve)
H3K27me3 LOSS

Question 3

Synovial Sarcoma

Answer 3

TLE1 (sensitive but not specific)

SS18-SSx and SSX c-terminus now have IHC

Question 4

Leydig cell tumour

Answer 4

Inhibin +
Calretinin +
Melan A +
WT1 +

Question 5

Yolk sac tumour

Answer 5

CK +
ALP +
SALL4 +
PLAP +
Glypican 3+

Question 6

Embryonal carcinoma

Answer 6

CD30+
OCT3/4+
PLAP and SALL4 +

Question 7

Acinic cell carcinoma

Answer 7

PAS+ granules (diastase resistant)
DOG1 +
S100 -
Mammoglobin -

Question 8

Secretory carcinoma (salivary gland)

Answer 8

mammoglobin +
S100+
p63 -
DOG1 -

Question 9

Polymorphous carcinoma, low grade

Answer 9

p63 +, S100+, SOX10 +, panCK

p40 -

Question 10

Thymoma

Answer 10

CK7 +, CD15+ (Type A)
BCL2+ (Type A and C)
CK5/6

Question 11

Thymic carcinoma

Answer 11

CK18, CD5, CD117, MUC1, GLUT1 +

Question 12

Epithelioid hemangioendothelioma

Answer 12

CAMTA1 +

Also usually vascular markers +

Question 13

Infantile hemangioma

Answer 13

GLUT1 +

Question 14

Low grade fibromyxoid sarcoma

Answer 14

MUC4 +

Question 15

Epithelioid sarcoma

Answer 15

CK+
EMA+
CD34 +/-
Loss of INI1

Question 16

Extrarenal rhabdoid tumour

Answer 16

CK +
EMA +
INI1 loss

Question 17

Pituitary adenoma

Answer 17

General Neuroendocrine markers +
Hormones: GH, PRL, TSH-β, FSH-β, LH-β, ACTH
Loss of acinar structure on reticulin stain

Question 18

Mycosis fungoides

Answer 18

CD3 and CD4+
CD7 -
May lose other T cell markers eg CD5
Clonal TCR gene rearrangements

Question 19

FNH

Answer 19

Glutamine synthetase - map like +

Question 20

Breast myofibroblastoma

Answer 20

CD34+
SMA, Desmin +
Hormone receptors +
B catenin -

Question 21

Acinar cell carcinoma pancreas

Answer 21

BCL10+
Trypsin +
Chymotrypsin +
PASD + granules

Question 22

pancreatoblastoma

Answer 22

Acinar areas: PASD + granules, enzymes +, BCL10+
Squamoid nests: EMA +, B catenin +
Also neuroendocrine component

Question 23

Endometrial stromal sarc

Answer 23

CD10 + (50%, more so in low grade, but can be + in LMS)
Cyclin D1 (more so in high grade)
Desmin can be focal +

Question 24

Low grade ESS

Answer 24

JAZF1

Question 25

High grade ESS

Answer 25

YWHAE, BCOR others

Question 26

DCIS

Answer 26

ER strong diffuse | CK5/6 negative

Question 27

Adrenal cortex

Answer 27

Inhibin, melan A, BCL2 + Weak synaptophysin + Chromogranin + SF1 best screening IHC?

Question 28

Medullary Thyroid Ca

Answer 28

TTF1, chromogranin, Synaptophyin, CK, CD56, calcitonin + | Thyroglobulin -

Question 29

Adenoid cystic carcinoma

Answer 29

CD117+ myoepithelial cells | Cyclin D1 + ??

Question 30

Pulmonary pneumocytoma

Answer 30

TTF1 + epithelium and storm | CK + epithelium only

Question 31

Lung mucinous adenocarcinnoma

Answer 31

Usually TTF1- Often CK20+ as well as CK7+ Can't rely on IHC to differentiate site of origin

Question 32

Thymoma

Answer 32

p63+ Pax8+ CD3+ T cells

Question 33

Thymic carcinoma

Answer 33

CD117+ | Looks like various types of carcinoma

Question 34

dVIN

Answer 34

High grade by definition | p53 null or strong diffuse + in basal cells (lower 1/3)

Question 35

Chondroblastoma

Answer 35

H3.3 K36M + in mononuclear cells

Question 36

GCT of bone

Answer 36

H3F3 G34W

Question 37

Chordoma

Answer 37

CK + S100+ Brachyury +

Question 38

Ewing sarcoma

Answer 38

CD99 + membranous FLI1+ nuclear NKX2.2 + Tdt-

Question 39

Spindle cell lesions of the breast

Answer 39

Myofibroblastoma - CD34+, Desmin+, ER/PR/AR+ PT - CD34+ Spindle Ca - CK5/6 Also, pASH, scar

Question 40

Oncocytic renal neoplasms

Answer 40

Chromophobe: CK7+, Hales+, CD117+ Oncocytoma: CK7-, Hales -, CD117+ CCRCC: CK7-, Hales-, CD10+, CD117-

Question 41

Solid pseudopapillary neoplasm

Answer 41

``` PASD+ globules Nuclear beta catenin CD10+ cytoplasmic ECAD loss ER+ SYN can be + but chromo - ```

Question 42

Ependymoma

Answer 42

``` Olig2 - Sox10 - GFAP + EMA + dot like H3K27ME3 - loss signifies type A ```

Question 43

Meningioma

Answer 43

SSRT1