Solitary thyroid nodules

Does a joint ultrasound guided cytology clinic optimize the cytological evaluation of head and neck masses?

AIM

To compare the results of fine-needle aspiration (FNA) of head and neck masses performed in an ultrasound-guided cytology clinic (USGCC) staffed by a radiologist and pathologist to those obtained with specimens sent from other sources.

METHODS

Comparison of broad-category FNA diagnoses (malignant, uncertain, benign or inadequate) with the patient's ultimate clinical or pathological outcome. Because FNA outcomes are semi-quantitative, accuracy of the procedure (the proportion of all tests resulting in a true- positive or negative fine-needle aspirate) is a better measure than sensitivity or specificity. Specimens (n = 292) from the first 2 years of the USGCC are compared with 600 specimens received from other sources over the previous 4 years.

RESULTS

Accuracy was 23.4% better for specimens from the USGCC compared with those obtained by clinician guided aspiration (83.9%, 95% CI 79.7-88.1%, vs 60.5%, 95% CI 56.6-64.4%). There was an 84% reduction in inadequate specimens (from 21.5% to 3.4%). The proportion resulting in an uncertain result did not alter; 12.0% for USGCC and 11.9% for clinician-derived specimens. Improvement in accurate identification of salivary gland, lymph node, soft tissue and thyroid pathology was 27.0%, 21.2%, 18.3% and 15.8% respectively.

CONCLUSIONS

The common practice of FNA performed by clinicians produces sub-optimal results in head and neck masses. A combined approach of ultrasound-guided fine-needle aspiration of head and neck masses, with immediate assessment of the material by a pathologist, is more accurate than with specimens obtained in other ways. If the results of FNA are to be incorporated into clinical decision making, the samples are best obtained using the USGCC model.

Clinical features associated with an increased risk of thyroid malignancy in patients with follicular neoplasia by fine-needle aspiration

The application of fine-needle aspiration (FNA) to the evaluation of the thyroid nodule has greatly enhanced the ability of the clinician to appropriately select patients for thyroidectomy. However, despite extensive experience with thyroid FNA, the cytological distinction of benign from malignant follicular neoplasia remains problematic. As a result, most patients with FNA findings of a follicular neoplasm are referred for thyroidectomy. The goal of the present study was to develop clinical criteria capable of predicting malignancy in patients with an FNA diagnosis of follicular neoplasm. Among 1121 patients undergoing thyroid FNA at two large teaching centers during the period 1990 to 1995, 149 patients had cytological findings consistent with a follicular neoplasm. Among 103 patients referred for thyroidectomy, 22 (21%) were found to have a malignancy in the biopsied nodule. Among patients subjected to thyroidectomy, the risk of malignancy was significantly higher when follicular neoplasia was present in a male (43% vs. 16% for females, p = 0.007), when the nodule was greater than 4 cm to palpation (40% vs. 13% for nodules less than 4 cm, p = 0.03), or when the nodule was judged to be solitary by palpation (25% vs. 6% for a dominant nodule in a multinodular goiter, p = 0.02). Bayesian analysis of the data reveals that after an FNA showing a follicular neoplasm, the risk of malignancy in males with large nodules was nearly 80%, compared with a rate of only 3% in females with small nodules. These results suggest that clinical features including gender, nodule size, and character of the gland by palpation can be systematically integrated into the decision analysis, thereby improving the selection of patients for surgical referral.