Table 2

Immunohistochemical (IHC) markers in the differential diagnosis of ovarian tumours

Primary ovarian tumours
LGSC+++wtwtwt−/++ KRAS mut, BRAF mut
EMC++wt>MM>wtM>wt+PTEN and MMR loss
Presence of endometriosis
CCC+−/+wtM>wtwt+Napsin A, HNF1β, AMACR
MC+wt>Mwtwt++−/+Presence of teratoma or Brenner tumour
SMT++wtM>wtwt+Presence of endometriosis
GCT/SCST−/+++/−wtwtwt+Inhibin, SF1, FOXL2 mut (GCT), DICER1 mut (SCST), EMA
SCC-HT++Mwtwt+SMARCA4 (BRG1) loss
Metastatic adenocarcinomas
Colorectalwt>MwtM>wt++CDX2, SATB2
BiliopancreaticM>wtwtwt+++SMAD4 (DPC4) loss
Breast+/−wt>Mwtwt+GCDFP15, mammaglobin
Lungwt>Mwtwt+TTF1, Napsin A
Kidney++wtwtwt−/+CD10, vimentin, HIF1β
Endocervix+−/+wt>Mwtwt++p16, HPV
Uterine EMC++wt>MM>wtM>wt+Vimentin, PTEN and MMR loss
  • ARID1A M consists in the loss of IHC staining, while ARID1A wt is nuclear staining. β-cat M is nuclear positivity; β-cat wt is cytoplasm, membrane positivity or negativity. p53 M corresponds to intense and diffuse positivity in ≥60% of cells or complete negativity; p53 wt is the presence of rare cells weakly positive or positivity in <60% of cells.

  • *PAX8 is also expressed in kidney, thyroid, parathyroid and thymic carcinomas.

  • †WT1 stains also normal mesothelium, kidney, their derived neoplasias and desmoplastic small round cell tumour.

  • β-cat, β-catenin; calr, calretinin; CCC, clear cell carcinoma; CK, cytokeratin; EMC, endometrioid carcinoma; GCT/SCST, granulosa cell tumour/sex-cord stromal tumour; HGSC, high-grade serous carcinoma; LGSC, low-grade serous carcinoma; M, mutant pattern; MC, mucinous carcinoma; MMR, DNA mismatch repair genes; mut, mutation; SCC-HT, small cell carcinoma of hypercalcaemic type; SMT, seromucinous tumour; USC, uterine serous carcinoma; wt, wild-type pattern.