Salivary glands

Question 1

benign mimics of malignancy

Answer 1

FNA (necrosis, pseudoinvasion)

radiation atypia

mucinous metaplasia (esp Warthin/PA) vs mucoepidermoid ca

squamous metaplasia (esp Warthin/PA) vs metastatic SCC

necrotizing sialometaplasia vs SCC/mucoepidermoid ca

clear cell oncocytoma

benign inclusions in LN (incl Warthin in LN)

Question 2

malignant mimics of benign

Answer 2

LG mucoepidermoid ca vs chronic sialadenitis

cystic acinic cell ca vs benign cyst

ACC/EME vs PA/basal cell adenoma

oncocytic AcCC/MEC vs oncocytoma

mucoepidermoid ca vs mucocele

ca ex PA

Question 3

basaloid neoplasms

Answer 3

basal cell adenoma/ca

canalicular adenoma

PA
adenoid cystic ca

peripheral ameloblastoma

skin adnexal tumours

Question 4

Immunos and FISH for neoplasms

Answer 4

oncocytoma: PTAH+

acinic cell ca: DOG1

mucoepidermoid ca: PASD+ mucin, MAML2 FISH

adenoid cystic ca: MYB FISH

MASC (now ‘secretory carcinoma’): ETV6 FISH

salivary duct carcinoma: AR, HER2, GCDFP

Question 5

oncocytic neoplasms

Answer 5

oncocytoma

Warthin tumour

acinic cell ca

mucoepidermoid ca

oncocytic ca (dx of exclusion)

Question 6

spindle cell lesions

Answer 6

myoepithelioma

schwannoma

SFT

nodular fasciitis

IMT

spindle cell ca

melanoma

Question 7

plasmacytoid lesions

Answer 7

PA and myoepithelioma (plasmacytoid hyaline cells)

plasmacytoma

rhabdomyosarcoma

melanoma

Question 8

HG malignant lesions

Answer 8

salivary duct ca

HG mucoepidermoid

adenocarcinoma NOS

ca ex PA

dedifferentiated ACC/PLGA/AcCC

Question 9

pleomorphic adenoma vs BCA/myoepithelioma

Answer 9

PA: epithelium, myoepithelium and stroma (chondromyxoid stroma diagnostic)

Question 10

chronic sialadenitis vs LG MEC

Answer 10

CS: lobular architecture

Question 11

adenoid cystic ca vs PLGA

Answer 11

ACC: abluminal cell component (p63+), EMA on gland lumen, high NC ratio, more hyperchromatic

PLGA: one cell type, strong diffuse s100

Question 12

inflammatory/LE lesions

Answer 12

chronic sialadenitis (obstruction)

chronic sclerosing sialadenitis/IgG4: plasma cells

lymphoepithelial sialadenitis (benign LE lesion)

MALT

lymphoepithelial ca

large cell lymphoma

Question 13

lymphoepithelial ca vs metastatic NPC

Answer 13

same histology, both EBV

clinical and radiologic distinction

Question 14

MALT lymphoma vs LESA

Answer 14

MALT lymphoma: collars of monocytoid B cells, cavitation of epithelial islands, infiltration of septa and nerves, diffuse sheets B cells, aberrant IHC (eg CD43)

Question 15

circumscribed tumours with dual cell type

Answer 15

PA: melting into stroma, +/-chrondroid matrix, +/-plasmacytoid hyaline cells

basal cell adenoma: no ‘melting’, no chrondroid, no PHCs

Warthin tumour: oncocytic, papillary, lymphoid stroma

Question 16

infiltrative tumours with dual cell types

Answer 16

adenoid cystic ca: basaloid abluminal cells predominate, cribriform

E-ME ca: large clear abluminal cells, cribriform rare

basal cell adenocarcinoma: basaloid cells predominate, jigsaw islands

Question 17

luminal vs abluminal markers

Answer 17

luminal: EMA, CEA

abluminal (myoepithelial): HMWCK, p63, actin, calponin, s100, GFAP

abluminal (basal cells): HMWCK, p63 (myoid/s100/ GFAP - )

Question 18

mucoepidermoid ca grading (Brandwein)

Answer 18

1: intermediate, 2 or more: high

aggressive invasion

intracystic <25%

atypia++

LVI

PNI

bone invasion

mitoses >4/10

necrosis

Question 19

Answer 19

(mammary analogue) secretory carcinoma: microcystic or papillary-cystic pattern, no basophilic granules as in AcCC, call on morphology if s100/mammaglobin+ (don’t need translocation)

Question 20

Answer 20

salivary duct carcinoma: looks like intraductal and invasive breast Ca, AR/HER2 +

Question 21

upper lip tumours

Answer 21

angioleiomyoma

canalicular adenoma

benign cysts (lots of types)

Question 22

clear cell tumours (with morph/IHC/genetics)

Answer 22

AcCC: DOG2, SOX10

MEC: MAML2

EME: biphasic

myoepithelial tumours: EWSR1

oncocytoma

clear cell adenoca: ATF1 fusion

mets (esp RCC)