Endobronchial Ultrasound-guided Mediastinal Lymph Nodal Cryobiopsy in Patients With Nondiagnostic/Inadequate Rapid On-site Evaluation: A New Step in the Diagnostic Algorithm.

Background: Endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) is considered the investigation of choice for sampling mediastinal nodes. A major drawback of EBUS-TBNA is its lower diagnostic yield for lymphoma and benign diseases. EBUS-guided mediastinal cryobiopsy (EBUS-MCB) is a novel technique that provides larger nodal biopsy samples, with an acceptable safety profile. In this study, we aimed to evaluate the diagnostic yield of EBUS-MCB in patients with an inconclusive rapid on-site evaluation (ROSE).

Methods: This is a prospective study of patients who underwent EBUS-TBNA for undiagnosed mediastinal lymphadenopathy. Patients in whom ROSE did not yield a diagnosis (nondiagnostic ROSE) or ROSE revealed scanty atypical cells (inadequate ROSE) were subjected to EBUS-MCB. The diagnostic yield, adequacy, and complications of EBUS-MCB were analyzed.

Results: Of the 196 patients undergoing EBUS-TBNA, 46 patients underwent EBUS-MCB. Thirty-two cases underwent EBUS-MCB for a nondiagnostic ROSE. EBUS-MCB confirmed the diagnosis in 19/32 (59.3%) cases. The additive diagnostic yield of EBUS-MCB over EBUS-TBNA was 43.7% (14/32 cases). In all 14 cases where EBUS-MCB was performed for an inadequate ROSE, the material obtained by EBUS-MCB was adequate for ancillary studies. The most common complication observed was a minor bleed in 13 cases.

Conclusion: EBUS-MCB has a diagnostic yield of 59.3% when performed in cases with a nondiagnostic EBUS-ROSE. The tissue obtained by EBUS-MCB is adequate for ancillary studies. We propose EBUS-MCB as an additional diagnostic step in cases with an inconclusive ROSE while performing EBUS-TBNA. Larger studies are, however, needed before EBUS-MCB can be incorporated in the diagnostic algorithm for the evaluation of mediastinal lesions.