Mesothelioma Diagnosis Differential Diagnosis

Question 1

Which malignancy most commonly mimics pleural mesothelioma on imaging and requires IHC for differentiation?

Accepted Answer

Metastatic lung adenocarcinoma

Answer

Primary lung squamous cell carcinoma

Answer

Pulmonary carcinoid

Answer

Primary pleural lymphoma

Question 2

Which IHC profile helps distinguish pleural mesothelioma (positive) from metastatic adenocarcinoma (negative)?

Accepted Answer

Calretinin positive, CEA negative

Answer

TTF-1 positive, calretinin negative

Answer

CEA positive, WT1 negative

Answer

MOC-31 positive, D2-40 negative

Question 3

Reactive mesothelial hyperplasia must be distinguished from mesothelioma because:

Accepted Answer

It is benign and does not require cancer treatment

Answer

It has worse prognosis than mesothelioma

Answer

It always progresses to mesothelioma

Answer

It cannot be sampled by biopsy

Question 4

Which condition most commonly causes benign pleural thickening that mimics mesothelioma on imaging?

Accepted Answer

Fibrothorax from prior empyema or hemothorax

Answer

Pulmonary embolism

Answer

Spontaneous pneumothorax

Answer

Pulmonary sarcoidosis

Question 5

Solitary fibrous tumor of the pleura (SFTP) is distinguished from mesothelioma by which key feature?

Accepted Answer

It is usually localized and has a pedunculated attachment to the pleura

Answer

It is always malignant

Answer

It is diffuse and bilateral

Answer

It always occurs in asbestos-exposed workers

Question 6

Which IHC marker strongly supports synovial sarcoma over sarcomatoid mesothelioma in a chest wall/pleural spindle cell tumor?

Accepted Answer

TLE1 positivity with SYT-SSX fusion on FISH

Answer

Pancytokeratin positivity alone

Answer

D2-40 positivity

Answer

BAP1 loss