Value of electron microscopy in cytologic diagnosis of fine-needle biopsy

Fine-needle biopsy in 14 consecutive patients with suspected malignancies were evaluated by routine cytology and electron microscopy. A protocol is described in which material from fine-needle biopsy can be held in glutaraldehyde and later processed for electron microscopy if necessary. Adequate tissue for electron microscopy was obtained in 12 of 14 cases. Specific classification of the tumor cells in these cases was achieved through electron microscopy. In six cases electron microscopy provided a more certain diagnosis than cytology alone. In two cases electron microscopy had significant impact on diagnosis and clinical management. The opportunity to examine tissues with electron microscopy increased the utility and specificity of the fine-needle technique without adding to patient discomfort or the cost of a second procedure.