Nonpalpable Thyroid Nodules Research Articles

Indications and limits of ultrasound-guided cytology in the management of nonpalpable thyroid nodules.

Although ultrasound (US)-guided fine needle aspiration biopsy (FNAB) is widely prescribed in nonpalpable thyroid nodules, the goal of this study was to define precisely the indications and limits of US-FNAB in a series of 450 nonpalpable nodules. Among 94 surgically controlled cases, 20 (8 infracentimetric and 12 centimetric or supracentimetric) carcinomas were diagnosed. The diagnosis of malignancy was successfully made by US-FNAB in 16 of 20 carcinomas, 3 were missed because of insufficient cytological material, and 1 was misdiagnosed. US-FNAB sensitivity and specificity were 94% and 63%, respectively. A logistic model indicated that nodule size (P < 0.6) was not associated with histological diagnosis, but that solid hypoechoic features were more likely to be malignant (P < 0.0003), with US sensitivity and specificity for malignancy of 80% and 70%, respectively. Logistic regression indicated that adequate cytological material significantly increased with nodule size (P < 0.0001). This result outlined the limits of US-FNAB in small nodules. Hence, indication of US-FNAB appears judicious in centimetric or supracentimetric nodules or in solid and hypoechoic ones. Such a management would allow the discovery of 15 of 20 carcinomas and would avoid 16% of unnecessary biopsies.

Indications and Limits of Ultrasound-Guided Cytology in the Management of Nonpalpable Thyroid Nodules

Indications and Limits of Ultrasound-Guided Cytology in the Management of Nonpalpable Thyroid Nodules

The role of ultrasonography-guided fine-needle aspiration biopsy in the management of nonpalpable and palpable thyroid nodules.

The introduction of highly sensitive imaging techniques has made it possible to detect many nonpalpable thyroid nodules (non-PTN). We investigated the value of ultrasound-guided fine-needle aspiration biopsy (US-guided FNAB) as a diagnostic tool in the management of non-PTN as well as palpable thyroid nodules (PTN) that were considered difficult to aspirate without guidance. US-guided FNAB was performed on a total of 119 nodules (71 palpable and 48 nonpalpable) from 119 patients between 1992 and 1996. All available clinical and follow-up data were reviewed. Surgical follow-up was available in 24 cases. The patients included 100 females and 19 males ranging in age from 9 to 81 years (average, 51 years). FNA diagnoses (PTN versus non-PTN) included papillary carcinoma (12.7% [9/71] versus 4.2% [2/48], follicular neoplasm (16.9% [12/71] versus 0%), medullary carcinoma (1.4% [1/71] versus 0%), atypical cytology (5.6% [4/71] versus 2.1% [1/48], non-neoplastic thyroid (63.4% [45/71] versus 85.4% [41/48]) and unsatisfactory (0% versus 8.3% [4/48]). In 2 cases of occult papillary carcinoma, risk factors included radiation exposure (1 case) and a newly developed nodule during follow-up for hypothyroidism (1 case). Subsequent surgical follow-up (24 cases) confirmed the FNA findings, except for a case of Hürthle cell adenoma and 1 of Hashimoto's thyroiditis diagnosed as papillary carcinoma and follicular neoplasm, respectively. US-guided FNAB in most non-PTN are diagnosed as benign. For most patients with non-PTN and without any high-risk factors, a conservative approach such as clinical follow-up may be a more cost effective and logical approach. In contrast, US-guided FNAB is more useful in diagnosing biologically significant lesions in PTN that may be difficult to aspirate without guidance.

Thyroid incidentalomas: management approaches to nonpalpable nodules discovered incidentally on thyroid imaging.

The introduction of highly sensitive imaging techniques has made it possible to detect many non-palpable nodules, or "incidentalomas," in the thyroid. Discovery of these lesions raises concerns about their malignancy, but the optimal strategy for managing these lesions has not been clearly established. To review evidence about incidentalomas, including prevalence and risk for malignancy, and to provide recommendations for their evaluation and treatment. Literature searches for relevant articles published in the past 15 years in major English-language medical journals, review of selected articles published before this period, and reviews of bibliographies in text-books. Three studies on autopsy findings, 11 studies on ultrasonographic findings, and other reports on nonpalpable thyroid nodules were included. Data on the prevalence of nodules on autopsy and in ultrasonographic series, palpation compared with ultrasonography, the risk for malignancy in nodules found in irradiated glands, the natural history of thyroid nodules, and the prevalence of occult cancer were collated and reviewed. Prevalence of thyroid incidentalomas estimated from autopsy studies ranges from 30% to 60%. Studies comparing clinical palpation with thyroid imaging show a prevalence of 13% to 50%. Prospective studies of randomly selected patients have reported a prevalence of 19% to 67%. The risk for malignancy in asymptomatic nodules found in nonirradiated glands is 0.45% to 13% (mean +/- SD, 3.9% +/- 4.1%). High-resolution ultrasonography is sensitive and capable of detecting many small, nonpalpable thyroid nodules. Most of these lesions are benign. For most patients with nonpalpable nodules that are incidentally detected by thyroid imaging, simple follow-up neck palpation is sufficient.