Stains And Markers

Question 1

Desmin positive
+
Myogenin positive

Answer 1

Rhabdomyosarcoma

Question 2

CD99

Vimentin

Answer 2

Markers for Ewing sarcoma/primitive neuroectodermal tumor (PNET)

Question 3

Keratin positive

Answer 3

Synovial sarcoma

Question 4

Synaptophysin

Answer 4

May be positive in PNET or Neuroblastoma

Medulloblastoma

Question 5

Small round blue cells with diffuse myogenin staining

Answer 5

Alveolar rhabdomyosarcom

Question 6

IgG, cd19, cd20, cd22, cd30, cd79a, PAX-5, BCL-6, cMYC combo

Answer 6

Diffuse large B cell lymphoma

Question 7

CD15 and CD30

Answer 7

Seen in classic Hodgkin lymphoma

Question 8

CD30 with T cell markers

Answer 8

Anaplastic large cell lymphoma
t(2;5)(p23;q35)
Commonly NPM-ALk fusion gene

Question 9

t(14;18) translocation
Ki67 stain < 95%

Answer 9

DLBCL

Question 10

Nondestructive phagocytosis of lymphocytes or erythrocytes

Answer 10

Sinus histiocytosis with massive lymphadenopathy (Rosai-Dorfman disease - accumulates in neck, skin, other organs ie bone, cns)

Histiocytes stain + for cd68(KP-1), cd163, S100
Neg for cd1a

Question 11

Cd1a positive

Answer 11

LCH

Also CD207+

Birbeck granules on light microscopy of LCH specimen

Question 12

Aberrations of MAPK
Brain tumor

Answer 12

Low grade gliomas
(MAPK pathway involves BRAF)

Question 13

Megakaryocytic marker characteristic of acute magakaryoblastic leukemia (AMKL)

Answer 13

CD41
CD42
CD61
AML type Common in trisomy 21

Question 14

BCOR- CCNB3
Solid tumor

Answer 14

Round cell sarcoma - less aggressive than many other EWS-like sarcoma

Tx: doxo and ifos without interval compression