Abstract No. 564 Transsternal Core Biopsy of Anterior Mediastinal Masses: Safe and Effective

The anterior mediastinum is considered a difficult anatomic location to target due to its position behind the sternum, between the lungs, and anterior to the aorta and heart. The purpose was to evaluate the safety and diagnostic accuracy of percutaneous transsternal anterior mediastinal core biopsy. Retrospective review of all percutaneous CT-guided transsternal mediastinal core biopsies performed at two academic centers was conducted. Core biopsy was performed with 18-gauge spring-loaded side-notch needles, either directly through a 17-gauge coaxial guide needle, or through 11- to 14-gauge bone biopsy coaxial guide needles. Sedation type, technical details, clinical history and follow up, and pathology results were reviewed. Sixteen biopsies were performed in 16 patients (8 women, 8 men; mean age 59 years), 9 of whom had pre-existing cancer diagnoses. Of them, 14 were performed with a side-notch needle bone through a bone biopsy coaxial needle and 2 were performed with a side-notch needle and its coaxial guide. The procedure was performed with moderate sedation in 6 cases, monitored anesthesia care in 7 cases, and general anesthesia in 3 cases. One procedural complication (pneumothorax requiring chest tube placement) was encountered. All other patients were discharged the same day. Of the 16 cases, 15 (94%) rendered a pathologic diagnosis. Eight cases were determined to be malignant (1 thymic carcinoid tumor, 1 high grade malignancy, 3 cases of lymphoma, 3 cases of lung cancer), 3 were benign, and there were 4 thymomas. In the one case with non-diagnostic tissue, only 1 core specimen was obtained; in 14/16 cases, 3 or more core specimens were obtained. Ancillary testing was requested in 6 cases; tissue was adequate in 4 of those cases. Four of the 16 patients later underwent surgery; 8 of the patients received diagnoses from the core biopsy that involved medical therapy or observation, precluding the need for surgery. CT-guided transsternal anterior mediastinal 18-gauge core biopsy is safe, feasible, and effective in rendering a diagnosis, and may be performed on an outpatient basis with moderate sedation. Obtaining at least 3 cores may optimize diagnostic accuracy. Percutaneous biopsy can help patients avoid unnecessary surgery.