What is the sensitivity and specificity of pleural biopsy in diagnosing tuberculosis (TB) and malignancy in patients with pleural effusion, and who performs the procedure?

Pleural Biopsy for Tuberculosis and Malignancy

For malignancy, thoracoscopic pleural biopsy achieves 95% sensitivity compared to 44% for closed needle biopsy and 62% for cytology alone, making it the preferred diagnostic approach when available. 1

A) Sensitivity and Specificity

1) Tuberculosis (TB)

Closed pleural biopsy (Abrams needle):

• Sensitivity: 75% for TB diagnosis 1
• At least 4 biopsy specimens from one site are required to optimize diagnostic accuracy 1
• Tissue must always be sent for TB culture in addition to histology 1

Thoracoscopic biopsy:

• Superior to closed biopsy but specific TB sensitivity data not separately reported in guidelines 1
• Allows visualization of granulomas and larger tissue samples 1

2) Malignancy

Closed pleural biopsy (blind Abrams needle):

• Sensitivity: 44-57% for malignancy 1
• Specificity: 100% 2
• Only increases diagnostic yield by 7-27% over cytology alone 1
• Negative predictive value: 44% 2

Image-guided closed pleural biopsy (CT or ultrasound-guided cutting needle):

• Sensitivity: 84-87% for malignancy 1, 2
• Specificity: 100% 2
• Negative predictive value: 75-80% 1, 2
• Pneumothorax rate: approximately 5% 1
• Significantly superior to blind Abrams biopsy (sensitivity 87% vs 47%, p=0.02) 2

Thoracoscopic pleural biopsy (medical or surgical):

• Sensitivity: 92-95% for malignancy 1, 3, 4
• Specificity: 93-100% 1
• Negative predictive value: 93-96% 1
• For mesothelioma specifically: 92% sensitivity 1
• No difference between medical (awake) thoracoscopy and surgical VATS in diagnostic yield 1
• No difference between rigid and semi-rigid thoracoscopy 1

Comparative hierarchy:

• Thoracoscopic biopsy is statistically superior to image-guided biopsy (p=0.04) 1
• Image-guided biopsy is superior to blind biopsy (p=0.01) 1
• Blind closed pleural biopsy should not be conducted 1

B) How to Perform and Who Does It

Procedural Approach Algorithm

Step 1: Initial evaluation

• If pleural fluid cytology is positive for malignancy, biopsy may not be needed unless additional tissue is required for molecular profiling 3, 4
• If cytology is negative but clinical suspicion for malignancy remains high, proceed to biopsy 1, 4

Step 2: Imaging assessment

• Perform contrast-enhanced CT scan before complete drainage of pleural fluid 1
• Look for: nodular pleural thickening (94% specificity), parietal pleural thickening >1 cm (94% specificity), mediastinal pleural involvement (88% specificity), or circumferential thickening (100% specificity) 1
• If focal pleural abnormalities are visible on CT, skip repeat thoracentesis and proceed directly to image-guided biopsy 4

Step 3: Choose biopsy method based on local availability and clinical context

Thoracoscopic biopsy (preferred when available):

• Provides highest diagnostic yield (95%) 1
• Allows simultaneous diagnosis and therapeutic intervention (talc pleurodesis) 1
• Enables biopsy of visceral, parietal, and diaphragmatic pleura under direct visualization 1, 4
• Provides sufficient tissue for immunohistochemistry and molecular profiling 3, 4
• Mandatory for suspected mesothelioma (cytology alone insufficient per International Mesothelioma Interest Group) 3, 4

Image-guided closed biopsy (alternative when thoracoscopy unavailable):

• Use when focal pleural abnormalities visible on imaging 1
• CT or ultrasound guidance both acceptable (no difference in diagnostic accuracy) 1
• Sensitivity 84-87% for malignancy 1, 2
• Less invasive, can be outpatient procedure 5
• Suitable for frail patients or those with pleural thickening but minimal fluid 5

Who Performs the Procedure

Medical thoracoscopy (awake, local anesthesia):

• Pulmonologists trained in the procedure 1
• Performed in endoscopy suite or procedure room 1
• Uses non-disposable rigid or semi-rigid instruments 1
• Requires thoracic surgery backup availability 1

Surgical thoracoscopy (VATS, general anesthesia):

• Cardiothoracic surgeons 1
• Performed in operating room 1
• More invasive and expensive than medical thoracoscopy 1
• No diagnostic advantage over medical thoracoscopy 1

Image-guided closed biopsy:

• Interventional radiologists (CT-guided) 1
• Pulmonologists or radiologists (ultrasound-guided) 1
• Can be performed by trained general physicians in some settings 5

Blind closed biopsy (Abrams needle):

• Historically performed by pulmonologists or general physicians 1
• Should no longer be used given superior alternatives 1
• Exception: May still be considered in high TB prevalence areas where resources are extremely limited 1, 6

Critical Procedural Considerations

For suspected mesothelioma:

• Mark all biopsy sites with Indian ink 1
• Biopsy tract should receive radiotherapy within 1 month if mesothelioma confirmed (40% risk of tract seeding without prophylactic radiation) 1

Common pitfalls:

• False-negative thoracoscopy results from insufficient/non-representative biopsies or extensive adhesions preventing access to tumor 1
• Adhesions often result from repeated therapeutic thoracentesis before definitive diagnosis 1
• In suspected malignancy with negative initial biopsy, up to 15% are subsequently diagnosed with malignancy (especially mesothelioma), requiring long-term radiological monitoring 4