Biopsies 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. The biopsy sample will by extracted by gently pulling of the probe.

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.

To determine, wheather cryobiopsy specimen can be obtained in each patient

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

Number of patients with a certain degree of bleeding from biopsy site, described as:

1 = slight, self-limited, 2 = moderate, requiring electrocautery intervention, 3 = severe, requiring interruption of the procedure, chest tube drainage and intravenous fluid resusucitation.