What is the primary purpose of a transthoracic needle biopsy of the lung?

The primary purpose of a transthoracic needle biopsy of the lung is to diagnose lung carcinoma. This procedure involves the use of a needle to obtain tissue samples from lung nodules or masses, which can then be examined histologically to identify the presence of cancerous cells. Early and accurate diagnosis of lung cancer is critical, as it can significantly influence treatment options and outcomes for the patient.

While transthoracic needle biopsies can be performed for other conditions such as infections or benign lesions, their main indication is to assess suspicious lung lesions for malignancy. The other options focus on different medical interventions or assessments: treating infections involves a different clinical approach, removing fluid from the pleura pertains to thoracentesis, and monitoring lung function generally requires spirometry or other non-invasive methods.