The purpose of this study is to assess the diagnostic yield and show the feasibility and safety of endobronchial biopsies using the flexible cryoprob and to assess the sensitivity of cryobiopsy compared with forceps biopsy

Flexible bronchoscopy is the diagnostic tool of choice to diagnose endobronchial malignancies. It allows inspection and biopsy of any endobronchial abnormalities under direct vision.

One of the main goals of diagnostic bronchoscopy, besides visualization of endobronchial abnormalities, is obtaining an adequate tissue samples from the suspicious lesions for cytohistological examination. Several techniques could be applied through the working channel of the flexible bronchoscopy such as forceps biopsy, brush, bronchial washing and transbronchial needle aspiration.Flexible bronchoscopy and the associated tissue sampling techniques are the most widespread procedures in the diagnosis of central lung cancer. Even though the specimens are obtained under direct vision, there is a significant failure rate, which therefore, requires repeated bronchoscopies. Concurrent application of different sampling techniques at bronchoscopy has been shown to improve the yield.

Diagnostic bronchoscopy with endobronchial forceps biopsy is primarily practiced in patients with suspected thoracic malignancy and visible endobronchial.

The major drawback of the forceps biopsy technique is the relatively small amount of tissue obtained, which is determined by the size of the forceps. Additionally, mechanical compression or crush artefacts from the instrument tip cause alterations of the tissue samples, which affect the quality of the histological analysis. Flexible cryoprobes were introduced as a new tool for bronchoscopic tissue sampling. It is used primarily for debulking and cryoextraction of malignant airway stenosis.

With this technique, the sample is collected while still being frozen with the tissue attached on the frozen tip of the probe. By this way, larger tissue samples can be taken from endobronchial lesions and artifact free. The molecular markers are also ions. Tissue samples obtained with cryoprobes are of good quality, size better preserved and well represented.

Inclusion Criteria:

- 1. Exophytic endobronchial tumor (endoscopically visible lesion)

3.Age>18 years old

Exclusion Criteria:

- 1.Patients, who refused to be included in this study or unfit for flexible bronchoscopy 2.patients with hemorrhagic diathesis (prothrombin concentration <50% and platelet count <80,000/mm 3).

3.Suspected connection of the lesion to large pulmonary blood vessels as seen on chest computed tomography scan