The fine needle aspiration cytology of mediastinal lesions.

Fine needle aspiration cytology was performed in 19 mediastinal lesions. Of seven malignant neoplasms six were correctly diagnosed as malignant and in five of these accurate tumor classification was possible. Of the 12 benign lesions only four cases, all thymomas, could be diagnosed cytologically. No false-positive diagnoses of malignancy were made. The only complication of the procedure was minor pneumothorax in two patients. In five cases the use of the technique spared the patient from more invasive diagnostic procedures; in several others, valuable information was obtained prior to surgery.