The Role of Rapid On-site Evaluation (ROSE) in EBUS/FNA and Concurrent Tissue Biopsies for Indeterminate Lung and Mediastinal Lesions

Summary: Introduction: EBUS/FNA is a minimally invasive technique for approachable lung masses and mediastinal lymph node sampling. The accompanying ROSE of the cytology is indispensable for successfully triaging EBUS/FNA specimens. The indeterminate categories (atypical and suspicious for malignancy) of WHO Reporting System for Lung Cytopathology harbor high risk of malignancy (ROM). ROSE can guide real time management and ensure timely diagnoses for indeterminate cases. Materials and Methods: EBUS/FNA cases (from 2015 to 2019) on mediastinal lymph node and lung mass sampling were gathered using the institutional pathology database. The ROSE cytology diagnoses, concurrent tissue biopsies and follow up biopsies of indeterminate categories were analyzed. Results: 1329 EBUS FNA specimens were collected, including 231 inadequate/nondiagnostic cases, 632 benign cases, 30 atypical cases, 41 suspicious for malignancy cases and 395 malignant cases. The indeterminate diagnoses (total 71 atypical and suspicious for malignancy cases) account for 5.3% of the ROSE diagnoses (atypical cases 2.3% and suspicious for malignancy cases 3.0%). Given the indeterminate categorization during EBUS procedures, concurrent EBUS guided tissue core/forceps biopsies were performed in 35 cases of the 71 cases (49.3%, including 14 atypical cases and 21 suspicious for malignancy cases) and 27 cases yielded malignant diagnoses (from 12 atypical cases and 15 suspicious for malignancy cases). 10 of 71 indeterminate cases (14.1%) had follow up EBUS procedures and yielded 2 malignant diagnoses from 7 atypical cases and 3 malignant diagnoses from 3 suspicious for malignancy cases. The ROMs of atypical cases and suspicious for malignancy cases were 66.7% and 75%, respectively. Conclusions: ROSE is critical for triaging EBUS procedures on mediastinal lymph node and lung mass sampling. Real time communication with proceduralists for indeterminate category cases facilitates concurrent tissue core/forceps biopsies and avoids delayed management of patients and repeated procedures.