Mesothelioma Therapy Diagnosis and Biomarkers for Mesothelioma 2 — Questions and Answers
Question 1: What is the gold standard method for confirming a diagnosis of mesothelioma?
- Analysis of pleural fluid cytology alone
- Tissue biopsy with histopathological and immunohistochemical examination (Correct answer)
- CT-guided fine needle aspiration cytology
- Serum biomarker panel testing
Correct answer: Tissue biopsy with histopathological and immunohistochemical examination
Tissue biopsy with histopathological examination including a panel of immunohistochemical stains is the gold standard for definitive mesothelioma diagnosis.
Question 2: Which procedure provides the highest diagnostic yield for mesothelioma by allowing direct visualization of the pleural surface and collection of multiple large biopsies?
- CT-guided needle biopsy
- Ultrasound-guided pleural biopsy
- Video-assisted thoracoscopic surgery (VATS) (Correct answer)
- Bronchoscopy with transbronchial biopsy
Correct answer: Video-assisted thoracoscopic surgery (VATS)
VATS allows direct visualization of the entire pleural surface and collection of multiple large tissue samples, providing the highest diagnostic yield for mesothelioma.
Question 3: Why is pleural fluid cytology alone considered insufficient for a definitive mesothelioma diagnosis?
- Pleural effusions are rarely seen in mesothelioma
- Cytology has limited sensitivity and cannot reliably distinguish malignant mesothelioma from reactive mesothelial proliferation without immunohistochemistry on tissue (Correct answer)
- Pleural fluid volumes are too small to allow adequate cellular analysis
- Cytology requires specialized equipment unavailable in most hospitals
Correct answer: Cytology has limited sensitivity and cannot reliably distinguish malignant mesothelioma from reactive mesothelial proliferation without immunohistochemistry on tissue
Pleural fluid cytology has low sensitivity for mesothelioma and lacks tissue architecture needed to reliably differentiate malignant mesothelioma from reactive mesothelial hyperplasia or metastatic adenocarcinoma.
Question 4: Which immunohistochemical markers are characteristically positive in epithelioid mesothelioma and help differentiate it from adenocarcinoma?
- TTF-1 and Napsin A
- CEA and MOC-31
- Calretinin and WT-1 (Correct answer)
- CK7 and CK20
Correct answer: Calretinin and WT-1
Calretinin and WT-1 are characteristically positive in epithelioid mesothelioma, supporting mesothelial origin and distinguishing it from adenocarcinoma.
Question 5: What is the most common histological subtype of mesothelioma?
- Sarcomatoid
- Biphasic (mixed)
- Epithelioid (Correct answer)
- Desmoplastic
Correct answer: Epithelioid
Epithelioid mesothelioma is the most common histological subtype, accounting for approximately 50-70% of all cases, and carries the most favorable prognosis.
Question 6: Which marker is characteristically positive in pulmonary adenocarcinoma but negative in mesothelioma, making it valuable in differential diagnosis?
- Calretinin
- Mesothelin
- TTF-1 (thyroid transcription factor-1) (Correct answer)
- Cytokeratin 5/6
Correct answer: TTF-1 (thyroid transcription factor-1)
TTF-1 is typically positive in primary pulmonary adenocarcinoma but negative in mesothelioma, making it a key marker to exclude lung cancer in the differential diagnosis.
Question 7: In which clinical scenario would medical thoracoscopy be preferred over CT-guided needle biopsy for mesothelioma diagnosis?
- When the patient has a large pleural effusion requiring both diagnosis and therapeutic drainage (Correct answer)
- When the patient has undergone previous ipsilateral thoracic surgery
- When focal pleural thickening is accessible from the chest wall without effusion
- When the patient cannot tolerate any form of sedation
Correct answer: When the patient has a large pleural effusion requiring both diagnosis and therapeutic drainage
Medical thoracoscopy is preferred when a large pleural effusion is present because it simultaneously provides diagnostic biopsies and therapeutic drainage, addressing both needs in a single procedure.
Mesothelioma Therapy Diagnosis and Biomarkers for Mesothelioma 2
What is the gold standard method for confirming a diagnosis of mesothelioma?