The Complementary Roles of EBUS-Guided Needle Aspiration, Mini-Forceps, and Cryobiopsy in the Investigation of Mediastinal Lesions

BACKGROUND: Convex probe endobronchial ultrasound (EBUS) bronchoscopy-guided transbronchial needle aspiration (TBNA) is the mainstay of mediastinal and hilar lesion sampling. EBUS-TBNA allows for the acquisition of cytologic material. However, certain clinicopathologic conditions require the acquisition of histopathologic specimens. This can be accomplished via EBUS-guided transbronchial mini-forceps biopsy (TBFB) and cryobiopsy (TBCB), but the incremental value of these modalities in various clinicopathologic conditions has yet to be explored. OBJECTIVE: Define the incremental value of EBUS-guided TBFB and TBCB over TBNA via evaluation of diagnostic yield, tissue quality, and adequacy for ancillary assays. METHODS: All patients who underwent EBUS-TBNA supplemented by TBFB and/or TBCB across two large academic centers were reviewed retrospectively. Cytology and histopathology tissue specimens were scrutinized for quantity, quality, tissue diagnosis, and adequacy for immunohistochemistry, molecular, and flow cytometry assays. Comparisons were made across TBNA, TBFB, and TBCB, as well as with a control group of EBUS-TBNA-only procedures for safety and procedural duration. RESULTS: A total of 204 lesions were sampled in 156 patients. Overall diagnostic yield was similar across TBNA, TBFB, and TBCB (P = 0.7); however, TBFB and TBCB outperformed TBNA for the diagnosis of lymphoproliferative and inflammatory conditions (P = 0.03 and P < 0.001, respectively). Compared with TBNA and TBFB, TBCB provided higher quality tissue for immunohistochemistry and molecular profiling assays (P = 0.002 and P < 0.001, respectively). TBNA adequacy for flow cytometry outperformed that of TBFB and TBCB (P < 0.001). Compared with TBFB, TBCB tissue specimens provided more diagnostic tissue (P < 0.0001) with less crush artifact (P < 0.0001). The rate and severity of procedure-related complications were similar across study cases and the EBUS-TBNA-only control group. CONCLUSION: For the sampling of mediastinal and hilar lesions, supplementation of EBUS-TBNA by TBFB or TBCB should be primarily considered when suspecting a lymphoproliferative or an inflammatory etiology or when high-quality tissue is required for predictive immunohistochemistry, and molecular assays. For accurate diagnosis and classification of lymphomas, the combination of TBNA for flow cytometry with TBCB for histopathologic interpretation appears to be optimal.