TABLE 2.
Typical expected immunohistochemical expression profiles for selected entities in the differential diagnosis of mediastinal SMARCA4‐DUT.
| Tumour type | Pan‐CK | EMA | CD45 | SOX‐10 | CD30 | SALL4 | CD34 | SOX2 | Claudin‐4 | Other pertinent expressed markers |
|---|---|---|---|---|---|---|---|---|---|---|
| SMARCA4‐DUT | Neg/Focal | Pos | Neg | Neg | Neg | Pos | Pos | Pos | Neg | SMARCB1/INI1 |
| Non‐Hodgkin B‐cell lymphoma | Neg | Neg | Pos | Neg | Neg/Pos | Neg | Neg | Neg | Neg | PAX‐5, CD20 |
| Classic Hodgkin lymphoma | Neg | Neg | Neg | Neg | Pos | Neg | Neg | Neg | Neg | CD15, PAX‐5 (weak) |
| Seminoma | Neg/Pos | Neg | Neg | Neg | Neg | Pos | Neg | Neg | Neg | OCT3/4, CD117, PLAP |
| Embryonal carcinoma | Pos | Neg | Neg | Neg/ Focal | Pos | Pos | Neg | Pos | Neg | OCT3/4 |
| Yolk sac tumour | Pos | Neg | Neg | Neg | Neg | Pos | Neg | Neg | Neg | Glypican 3, alpha‐ fetoprotein |
| SMARCA4‐ deficient adenocarcinoma | Pos | Pos | Neg | Neg | Neg | Neg | Neg | Neg/ Pos | Pos | CK7, HepPar1 |
| Thymic carcinoma | Pos | Pos | Neg | Neg | Neg | Neg | Neg | Pos | Pos | CK5/6, p63, CD5, CD117 |
| NUT carcinoma | Pos | Pos | Neg | Neg | Neg | Neg | Neg/ Pos | Pos | Neg | p63, p40, NUT1 |
| Mesothelioma | Pos | Pos | Neg | Neg | Neg | Neg | Neg | Neg/ Pos | Neg | CK5/6, Calretinin, D2‐40, WT‐1 |
| Metastatic melanoma | Neg | Neg | Neg | Pos | Neg | Neg | Neg | Pos/ Neg | Neg | S100, Melan A, HMB‐45 |
| Metastatic hepatocellular carcinoma | Pos/Neg* | Neg/Pos | Neg | Pos/Neg | Neg | Neg/Pos | Neg** | Pos/Neg | Neg | Arginase1, Glypican 3, HepPar1 |
Abbreviations: CK, cytokeratin; EMA, epithelial membrane antigen; HepPar1, hepatocyte specific antigen; HMB‐45, human melanoma black 45; INI1, integrase interactor 1; Neg, negative; NUT1, nuclear protein in testis 1; OCT3/4, octamer‐binding transcription factor 3/4; PAX‐5, paired box 5; PLAP, placental alkaline phosphatase; Pos, positive; SALL4, Spalt‐like transcription factor 4; SMARCA4‐DUT, SWI/SNF‐related, matrix associated actin dependent regulator of chromatin subfamily A member 4 deficient undifferentiated tumour; SMARCB1, SWI/SNF related, matrix associated actin dependent regulator of chromatin subfamily B member 1; SOX10, sex region Y‐related HMG‐box 10; SOX2, sex region Y‐related HMG‐box 2; WT‐1, Wilms tumour 1.
Depends on the specific cytokeratin clone, usually positive for MNF116 and CAM5.2, negative for AE1/AE3.
Tumour cells negative but positive in endothelial cells lining sinusoids.