Purpose or Case Report: Lymphoma is the most common mediastinal mass in children. Obtaining tissue for diagnosis can be challenging due to reported low diagnostic yield and risk of cardiorespiratory collapse, especially in the setting of anesthesia. We report our experience with biopsy of mediastinal masses, report the diagnostic rate for lymphoma and biopsy/anesthetic complications related to the procedure.
Methods & Materials: A retrospective review of image-guided core needle biopsy biopsies of mediastinal masses performed over the past 10 years. All interventional radiology patients <18 years old with final pathology result of lymphoma were included in the analysis(N=24).


Results: 27 cases (24 patients) were included (13 male). The median age at diagnosis was 15.4 years (IQR 12.14-16.49) and median weight 56 kg (IQR 42-59 kg). There were 24 primary diagnoses and 3 recurrences. Lesion volume measurement was available for 25/27 cases with a median of 539 mL (IQR 360 -877 mL). Tracheal deviation ranged from 0.6-3.3 cm from midline. Pre-biopsy airway narrowing was documented at the level of trachea (9), right bronchus (5), or left bronchus (12). Vascular compression was present in 16 patients (59.3%), of which superior vena cava compression was noted in 12(75%). 7 patients had pre-biopsy respiratory symptoms (cough, dyspnea, orthopnea, wheezing). The majority of procedures were performed in the operating room (19, 73.1%), with the remainder in the interventional radiology suite (5, 19.2%), CT suite or intensive care unit. Ultrasound guidance was used alone or in combination in all cases. Adjunctive imaging guidance included CT (2, 7.4%) and fluoroscopy (1, 3.7%), and was only used in recurrent disease. Mean number of biopsy passes was 8 (IQR 6-12) with 25/27 using coaxial technique. The diagnostic rate was 96.2% (26/27). In a single case, subsequent surgical biopsy was required for diagnosis confirmation. A single patient with known airway and vascular compression developed intra-procedural hypoxia and bradycardic arrest that responded to change in position with spontaneous return of circulation.
Conclusions: When alternative sources of histologic material are unavailable in the setting of suspected mediastinal lymphoma, image-guided biopsy has a high diagnostic yield. Comprehensive evaluation of mediastinal mass size, airway and vascular compression may assist prior to biopsy, as we encountered cardiovascular collapse in a single patient receiving monitored anesthesia care.