Pathologic Diagnosis and Genetic Analysis of a Lung Tumor Needle Biopsy Specimen Obtained Immediately After Radiofrequency Ablation

To evaluate the possibility of pathologic diagnosis and genetic analysis of percutaneous core-needle biopsy (CNB) lung tumor specimens obtained immediately after radiofrequency ablation (RFA). Patients who underwent CNB of lung tumors immediately after RFA from May 2013 to May 2016 were analyzed. There were 19 patients (8 men and 11 women; median age, 69 years; range, 52–88 years) and 19 lung tumors measuring 0.5–2.6 cm (median, 1.6 cm). Thirteen tumors were solid, and 6 were predominantly ground-glass opacity (GGO) on computed tomography. All specimens were pathologically examined using hematoxylin and eosin (H&E) staining and additional immunostaining, as necessary. The specimens were analyzed for EGFR and KRAS genetic mutations. The safety and technical success rate of the procedure and the possibility of pathologic diagnosis and genetic mutation analysis were evaluated. Major and minor complication rates were 11% (2/19) and 53% (10/19), respectively. Tumor cells were successfully obtained in 16 cases (84%, 16/19), and technical success rate was significantly lower for GGO-dominant tumors (50%, 3/6) compared with solid lesions (100%, 13/13, p = 0.02). Pathologic diagnosis was possible in 79% (15/19) of cases based on H&E staining alone (n = 12) and with additional immunostaining (n = 3). Although atypical cells were obtained, pathologic diagnosis could not be achieved in 1 case (5%, 1/19). Both EGFR and KRAS mutations could be analyzed in 74% (14/19) of the specimens. Pathologic diagnosis and genetic analysis could be performed even for lung tumor specimens obtained immediately after RFA.