Thallium-201 scan in evaluating thyroid nodules following equivocal fine-needle aspiration cytology

Does fine-needle aspiration cytology optimize the surgical management of thyroid disorders in endemic goiter region?

AIM

The aim of this study was to determine the diagnostic value of fine-needle aspiration cytology (FNAC) before thyroidectomy in an endemic goiter region.

METHODS

One hundred patients with preoperative FNAC of thyroid nodules who underwent thyroidectomy were recruited. FNAC were classified into five groups. 0, no thyroid cells; 1, normal thyroid cells; 2, degenerative thyroid cells without evidence of malignacy; 3, follicular or oncocytary neoplasia; and 4, malignant thyroid cells. FNAC was compared with postoperative histopathological diagnoses.

RESULTS

Only 76% of the FNAC allowed an adequate cytological examination. In 15 patients (15%), carcinomas were found in the postoperative histopathological diagnosis (including four follicular carcinomas). In the 48 patients of FNAC groups 3 and 4, nine carcinomas (18.7%) were found (including four follicular carcinomas). In the 28 patients of groups 1 and 2, there was only one papillary carcinoma (3.5%). In the 24 patients of group 0, there were two papillary, two follicular, and one anaplastic carcinomas (total of 20.8%). The sensitivity, specificity, and likelihood ratio (LR) of the FNAC for benign nodules were 90%, 40.9%, 0.24, respectively. The LR for malignant nodules was 13.2, and that for follicular neoplasia was 0.55.

CONCLUSIONS

Despite the high prevalence of carcinoma in an endemic goiter region, FNAC disappointed its diagnostic expectation. The lower specificity of FNAC may be caused by a higher prevalence of thyroid nodules in an endemic goiter region or by the absence of a specialized cytopathologist.

Preoperative assessment of thyroid nodules: role of ultrasonography and fine needle aspiration biopsy followed by cytology

PURPOSE

To evaluate the preoperative assessment of thyroid nodules using ultrasound studies and cytology of nodular aspirates.

SUBJECTS AND METHODS

2,468 patients with thyroid nodules were examined from 1999 to 2005. All patients were clinically examined and underwent ultrasonography followed by fine-needle aspiration biopsy (FNAB) and cytology.

RESULTS

Nodules larger than 10 mm were classified ultrasonographically in a 4-tier system and received a score according to the criterion of possible malignancy. Cytological examinations were conducted independently by 2 cytologists and classified as benign (score 1), indeterminate (score 2), suspicious (score 3), and malignant (score 6). Combining both scores, an index was generated that would indicate a higher probability of malignancy (benign, doubtful, suspicious, and malignant). Thyroid surgery was performed in 274 patients. Of those, 115 patients had a score of 2 to 5 and only 8 had a histological diagnosis of thyroid cancer (6.9%). For patients with a score of 5 (n = 51), 11.5% had a malignant lesion, and 51% of the 61 patients with a score of 6 had confirmed thyroid cancer. Of the 98 patients with a combined score of 7 to 10, 99% had a histological confirmation of malignancy.

CONCLUSIONS

The index score had a sensitivity of 94.1% and specificity of 77.5%. The overall accuracy was 85.8%. Therefore, we concluded that this methodology may improve the preoperative diagnosis of thyroid cancer in nodules larger than 10 mm. Association with other methods such as color Doppler echography, serum TSH concentration, galectin-3 expression analysis, and FDG/PET scan would be useful in avoiding the higher costs of thyroid surgical procedures.