Transmission electron microscopy of percutaneous fine needle aspirates from lung: a study of 70 cases.

Seventy consecutive lung fine needle aspirates (FNA) from 69 patients were examined by cytology/cell block histology, by transmission electron microscopy (TEM), and, where available, at histological follow up to determine the value of TEM in interpreting lung FNAs. Of 70 FNAs, 50 were suitable for TEM. Transmission electron microscopy was helpful in classifying seven of 10 poorly differentiated tumours, and two case histories are reported. In 26 of 30 well differentiated tumours TEM confirmed diagnosis by light microscopy. Two TEM false negatives, but no TEM false positives, were recorded. It is concluded that transmission electron microscopy of cells aspirated from lung can be helpful when unequivocal diagnosis has not been achieved.