Cryoiopsies will be obtained by flexible autoclavable cryoprobe 20416-032 (Erbokryo CA, ERBE, Germany) with 2.4 mm in diameter. The tip of the probe is cooled to -890C with nitrous oxide within seconds after footswitch activation.

Forceps biopsies will be obtained by flexible FB-55CD-1 Olympus forceps.

The tip of the cryoprobe will be attached to suspicious part of parietal pleura and activated by footswitch for 3 seconds. The frozen tissue is going to be extracted by gently pulling of the probe. The probe with the attached biopsy sample is going to be removed together with the thoracoscope through trocar. The biopsy sample will be released from the probe by thawing in the saline.

Forceps biopsy will be performed on usual way.

• diagnostic yield
• size of the biopsy specimens in mm2
• interpretability of biopsy specimens in histopathology terms: 1. easily interpretable (enough tissue with all elements required for diagnosis) 2. interpretable with some difficulty (less tissue or diagnostic elements - diagnosis less reliable) 3. interpretable with great difficulty (little tissue or scarce diagnostic elements - low reliability of diagnosis) 4. non-interpretable (diagnosis not possible)
• assessment of biopsy-related artifacts by describing the amount of unaltered tissue in quartiles

The degree of bleeding at the biopsy site will be assessed as 1 = slight, self-limited, 2 = moderate, requiring electrocautery intervention, 3 = severe, requiring interruption of the procedure, chest tube drainage and intravenous fluid resusucitation.