Introduction: Lung Cancer is the most common malignant disease in the world today, while at the same time it is the leading cause od death among all malignant diseases. In the Republic of Croatia, lung cancer is the third most common cause of death in men, after acute myocardial infarction and cerebrovascular insult, with a share of 18%. In women, lung cancer is the third most common malignant disease, while it ranks first in terms of mortality from malignant disease.

Aim: When lung cancer or metastases are detected, it is necessary to confirm that is a malignant disease and to analyze the type of tumor, so that it is possible to determine the most effective further therapy.

Methods:This has led to an increasing need for transthoracic biopsy due to the development of thoracic oncology and the determination of specific therapy depending on the type of tumor.

Results: Transthoracic biopsy under the control of computed tomography (MSCT) is an indispensable part of the diagnosis of numerous intrathoracic diseases, especially those of neoplastic etiology.

Conclusion: Given the objective limitations of bronhoscopy in the diagnosis of intrathoracic malignancies, maintly related to the specific localization of the process, transthoracic biopsy under the control of MSCT is an extremly important diagnostic method for significantly more invasive thoracic surgical procedures. It is also important to note that thoracic surgery is not directly available in most institutions in the Republic of Croatia.