To retrospectively evaluate the safety, diagnostic yield, and risk factors of diagnostic failure of computed tomography (CT) fluoroscopy-guided biopsies of anterior mediastinal masses.

Biopsy procedures and results of anterior mediastinal masses in 71 patients (32 women/39 men; mean [±standard deviation] age, 53.8±20.0years; range, 14–88years) were analyzed. Final diagnoses were based on surgical outcomes, imaging findings, or clinical follow-up findings. The biopsy results were compared with the final diagnosis, and the biopsy procedures grouped by pathologic findings into diagnostic success and failure groups. Multiple putative risk factors for diagnostic failure were then assessed.

Seventy-one biopsies (71 masses; mean size, 67.5±27.3mm; range 8.6–128.2mm) were analyzed. We identified 17 grade 1 and one grade 2 adverse events (25.4% overall) according to the National Cancer Institute Common Terminology Criteria for Adverse Events version 4.0. Sixty-nine biopsies (97.2%) provided samples fit for pathologic analysis. Diagnostic failure was found for eight (11.3%) masses; the 63 masses diagnosed successfully included thymic carcinoma (n=17), lung cancer (n=14), thymoma (n=12), malignant lymphoma (n=11), germ cell tumor (n=3), and others (n=6). Using a thinner needle (i.e., a 20-gauge needle) was the sole significant risk factor for diagnostic failure (P=0.039).

CT fluoroscopy-guided biopsy of anterior mediastinal masses was safe and had a high diagnostic yield; however, using a thinner biopsy needle significantly increased the risk of a failed diagnosis.