Fine needle aspiration in the management of benign thyroid cysts.

BACKGROUND: Resolution of cystic thyroid lesions after aspiration occurs in 8-45% of cases, the remainder require treatment for residual tumour or recurrent cysts. The aim of this study was to identify patient characteristics that predict cyst recurrence to enable these patients to undergo early surgery. METHODS: A retrospective analysis of 123 patients with benign thyroid cysts that were suitable for conservative management was undertaken. Demographic, clinical, ultrasound and fine needle aspiration cytology data were collated for patients who underwent surgery or were managed conservatively. Univariate and multivariate analyses were performed to identify factors predictive of cyst recurrence. RESULTS: Of the 123 patients, 43 underwent surgery consequent on cyst recurrence or persistent symptoms after aspiration, and 80 were treated by aspiration alone. There were 17 males and 106 females, of mean age 45.5 years. The mean cyst size was 27 mm. Those undergoing surgery had a significantly greater mean cyst size (P = 0.001). The only factor predicting cyst recurrence on univariate analysis was absence of follicular cells on initial aspiration (P = 0.005). Multivariate analysis confirmed absence of follicular cells as an independent characteristic predicting recurrence, the odds ratios for recurrence was 3.18 (95%CI 1.39-7.29). CONCLUSION: The present study suggests consideration of early surgery for patients with thyroid cysts with absence of follicular cells on initial cytology.

Fine-needle aspiration cytology of thyroid nodules: how useful is it?

BACKGROUND: Thyroid nodules are common and the principal method of diagnosis is fine-needle aspiration cytology (FNAC). METHODS: To determine the value of FNAC in the diagnosis of thyroid nodules, thyroid cytology of 253 patients with definitive histology after surgery was analyzed from 1992 to 2002. FNAC was correlated with histology and the sensitivity, specificity and likelihood ratios were calculated. The method of FNAC and number of non-diagnostic aspirates were noted. The frequency of thyroid cancer was investigated in male and females who presented with a solitary thyroid nodule. RESULTS: The overall sensitivity of FNAC detecting thyroid neoplasia was 55.0%, specificity 73.7% and accuracy 67.2%. Likelihood ratios indicate that a 'malignant' or 'suspicious for malignancy' cytology dramatically increase the pretest probability of thyroid neoplasia. There were no false positive 'malignant' FNAC. Ultrasound guided FNAC had a significantly lower non-diagnostic rate compared to freehand FNAC (P < 0.02). Of 22 males, 22.7% who proceeded to surgery for their solitary nodule had thyroid carcinoma compared with 11.9% of 167 females (P = 0.02). CONCLUSIONS: FNAC was essential to management in this series of patients. 'Malignant' or 'suspicious for malignancy' cytology are absolute indicators for thyroidectomy. FNAC should be undertaken with ultrasound guidance and if possible with a pathologist in attendance to assess sample adequacy. We recommend a high index of suspicion of thyroid cancer in the male patient who presents with a solitary nodule. If solitary nodules are to be observed, repeat FNAC should be undertaken because of the high false negative rate.

Does frozen section have a role in the intraoperative management of thyroid nodules?

BACKGROUND: Frozen section in thyroid surgery is used to make an intraoperative pathological diagnosis of malignancy in a thyroid nodule at the time of hemithyroidectomy. A positive diagnosis allows completion of thyroidectomy, thus avoiding reoperation. However, the use of fine needle aspiration cytology in making a preoperative diagnosis of cancer has resulted in the lack of a defined role for frozen section. We examined the role of frozen section as an adjunct to fine needle aspiration cytology in determining which cytological subset will benefit from frozen section. METHODS: All patients who underwent thyroidectomy between 1992 and 2000 by a single endocrine surgeon were reviewed. RESULTS: Two hundred and nine frozen sections were performed, of which 144 underwent preoperative fine needle aspiration cytology. Frozen sections reported 135 benign nodules, 59 follicular neoplasms, five specimens with suspicious histology and 10 cancers. Ten out of 20 thyroid cancers were correctly identified by frozen section (sensitivity: 50%; specificity: 100%), eight cancers were reported on frozen section as indeterminate and two benign. Of 144 fine needle aspiration cytological procedures, frozen section on seven suspicious aspirates identified two cancers, and frozen section on 70 follicular aspirates identified four cancers, allowing intraoperative conversions to total thyroidectomy. Frozen section on seven malignant aspirates confirmed four cancers but resulted in reoperation for three because of the indeterminate frozen section reports. There were no cancers found on 135 benign aspirates. CONCLUSIONS: Frozen section on benign aspirates is unhelpful in the management of thyroid nodules. It need not be performed for cytologically proven malignant thyroid nodules. Selective use of frozen section complements fine needle aspiration cytology findings of suspicious or follicular lesions, especially in the subset with papillary cancer, allowing one-stage total thyroidectomy.