The needle biopsy diagnosis of papillary thyroid carcinoma.

One hundred five cases of papillary thyroid carcinoma (PTC) were studied by needle biopsy and surgically confirmed in a 30-month period. Eight years were required to diagnose the same number of cases without the use of needle biopsies. Identification of clinically unsuspected cancer and confirmation of clinical "possible" cancer diagnoses accounted for 30% of this change. Seventy percent was accounted for by the increase in nodules referred for evaluation. The accuracy of fine-needle biopsy (FNB) improved with experience. Positive diagnoses of PTC were made in 19 of the first 35 PTCs and in 33 of the last 35. False-negative and unsatisfactory FNBs decreased from seven in the first third of the study to zero in the last third. Large-needle biopsy (LNB), initially used to check FNB, became less necessary as experience increased. Both FNB and LNB were more specific when papillary areas were included in the biopsy procedure, and approached the specificity of surgical biopsy. The increase in identifying PTC may require modification of the therapeutic implications of this diagnosis.