Cryobiopsy during flex-rigid pleuroscopy: an emerging alternative biopsy method in malignant pleural mesothelioma. A comparative study of pathology.

BACKGROUND: Malignant pleural mesothelioma (MPM) is rarely an asbestos-related cancer with a poor prognosis that is difficult to distinguish from some benign conditions by using conventional biopsy techniques. The purpose of this study was to evaluate the utility of a novel biopsy technique using a cryoprobe during flex-rigid pleuroscopy for diagnosing MPM.

METHODS: Consecutive patients who underwent pleural cryobiopsy during flex-rigid pleuroscopy from June through November 2017 to diagnose the cause of pleural effusion were collected. From these, cases ultimately diagnosed as MPM were selected. Pleural biopsies were performed by using conventional instruments followed by a cryoprobe. The obtained samples were histologically examined and compared with regard to the quality (sample size, tissue depth, and crush rate), immunohistochemical (IHC) staining, and p16 by fluorescence in situ hybridization (FISH).

RESULTS: In total, five patients ultimately diagnosed as MPM were enrolled. The sample collected was significantly larger for cryobiopsy than conventional biopsy (18.9 mm2 vs. 6.7 mm2, P < 0.001). Full-thickness biopsies were achieved in four cases by using cryobiopsy compared with one case by conventional biopsy. Moreover, the crush rate was significantly less for cryobiopsy than conventional biopsy (9% vs. 35%, P < 0.001). The results of IHC staining and p16 by FISH were similar between biopsy techniques. Cryobiopsy successfully led to accurate diagnosis of MPM in all cases, whereas conventional biopsy was diagnostic in one case. No severe complications developed after either biopsy technique.

CONCLUSION: Cryobiopsy during flex-rigid pleuroscopy is a feasible and convenient biopsy technique that supports precise diagnosis of MPM.