🎯 Background & Rationale
There has historically been no evidence-based standard or prospective data regarding the optimal number of pleural biopsies required during pleuroscopy (medical thoracoscopy) to achieve diagnostic adequacy. While historical dogma recommended obtaining 15 to 20 samples, contemporary practice has leaned toward more conservative sampling (median 4 to 10 biopsies) to mitigate risks such as bleeding, prolonged procedure times, and increased sedation requirements. This prospective study was designed to evaluate the cumulative diagnostic yield of sequential pleural biopsy aliquots to establish a more rational, evidence-based approach to pleural tissue sampling.
👥 Study Design & Population
- Study Type: Prospective, single-center observational pilot study.
- Population: 104 adult patients undergoing rigid pleuroscopy with pleural biopsy between December 2024 and December 2025 at a single center (Mount Sinai West, New York).
- Key Demographics: Median age 70.5 years (IQR 59–78); 55% male, 45% female; 55% had a known history of malignancy (18% lung cancer). The most common gross pleural abnormalities were diffuse pleural thickening (49%) and discrete nodules (23%).
📈 Methodology & Rigor
Procedures were performed using rigid pleuroscopy under moderate sedation. Biopsies were prospectively obtained using rigid cupped forceps and categorized into sequential aliquots by order of acquisition: Aliquot 1 (biopsies 1–3), Aliquot 2 (4–6), Aliquot 3 (7–9), and Aliquot 4 ($\ge 10$). Pathologists evaluated the specimens sequentially to determine the earliest aliquot that yielded a definitive diagnosis. Cumulative diagnostic yield, tissue requirements for comprehensive biomarker testing, and periprocedural complications were evaluated.
🔬 Key Findings
- Diagnostic Yield by Aliquot: A definitive diagnosis was achieved in all 104 patients (median 10 biopsies per procedure, IQR 6–14). Aliquot 1 ($\le 3$ biopsies) provided a definitive diagnosis in 93% of cases.
- Subsequent Aliquots: The remaining 7% of cases requiring further sampling were overwhelmingly associated with diffuse pleural disease (6 out of 7 cases) rather than discrete focal lesions.
- Biomarker Adequacy: Of 17 patients requiring comprehensive molecular/biomarker testing, 10 (59%) required tissue specimens from aliquots beyond the first.
- Complications: One patient experienced postprocedural bleeding managed conservatively with thoracentesis; no major complications were reported.
⚖️ Critical Appraisal
- Strengths: Prospective design, sequential aliquot tracking, and direct evaluation of modern tissue demands (such as molecular profiling for precision oncology).
- Limitations: It is a single-center pilot study utilizing exclusively rigid pleuroscopy, which limits generalizability to centers primarily utilizing flexi-rigid (semi-rigid) thoracoscopes (which possess smaller biopsy forceps). Furthermore, the observational nature means biopsy counts were driven by real-time clinical judgment rather than a strict randomized protocol, introducing potential selection bias.
💡 The Clinical Bottom Line
While the vast majority of pleural diagnoses (93%) can be established with 3 or fewer biopsies, interventional pulmonologists should tailor their sampling strategy to pleural morphology. Focal, discrete lesions allow for rapid, targeted diagnosis with minimal biopsies, whereas diffusely abnormal or grossly normal-appearing pleura—especially when malignancy is suspected or comprehensive biomarker profiling is required—demands broader, more extensive tissue acquisition.