Mesothelioma Diagnosis Differential Diagnosis 2

Question 1

Peritoneal mesothelioma must be differentiated from primary peritoneal carcinoma by which IHC finding?

Accepted Answer

Calretinin and WT1 positive vs. PAX8 and ER positive in carcinoma

Answer

CEA positivity in mesothelioma

Answer

CK20 in mesothelioma vs. CK7 in carcinoma

Answer

TTF-1 in mesothelioma

Question 2

Pleural involvement by breast carcinoma can be excluded in favor of mesothelioma by the absence of which markers?

Accepted Answer

ER, GATA3, and mammaglobin

Answer

Calretinin and WT1

Answer

D2-40 and CK5/6

Answer

TTF-1 and Napsin A

Question 3

Which rare pleural tumor is composed of lipomatous elements and must be distinguished from mesothelioma with lipomatous areas?

Accepted Answer

Well-differentiated liposarcoma

Answer

Epithelioid hemangioendothelioma

Answer

Desmoid tumor

Answer

Pleomorphic carcinoma

Question 4

Pleural epithelioid hemangioendothelioma (EHE) is distinguished from mesothelioma by positive staining for which marker?

Accepted Answer

CD31 and ERG (endothelial markers)

Answer

Calretinin

Answer

WT1

Answer

D2-40

Question 5

A pleural biopsy showing diffuse large B-cell lymphoma cells would be differentiated from mesothelioma by which finding?

Accepted Answer

CD20 positivity and cytokeratin negativity

Answer

Calretinin positivity

Answer

BAP1 loss

Answer

CDKN2A deletion

Question 6

Paraganglioma occurring in the posterior mediastinum may mimic mesothelioma on imaging; it is distinguished by positive staining for:

Accepted Answer

Synaptophysin and chromogranin A

Answer

Calretinin and WT1

Answer

CK5/6 and D2-40

Answer

TTF-1 and Napsin A