Risk of thyroid cancer in a lung cancer screening population of the National Lung Screening Trial according to the presence of incidental thyroid nodules detected on low-dose chest CT

PURPOSE

This study evaluated thyroid cancer risk in a lung cancer screening population according to the presence of an incidental thyroid nodule (ITN) detected on low-dose chest computed tomography (LDCT).

METHODS

Of 47,837 subjects who underwent LDCT, a lung cancer screening population according to the National Lung Screening Trial results was retrospectively enrolled. The prevalence of ITN on LDCT was calculated, and the ultrasonography (US)/fine-needle aspiration (FNA)-based risk of thyroid cancer according to the presence of ITN on LDCT was compared using the Fisher exact or Student t-test as appropriate.

RESULTS

Of the 2,329 subjects (female:male=44:2,285; mean age, 60.9±4.9 years), the prevalence of ITN on LDCT was 4.8% (111/2,329). The incidence of thyroid cancer was 0.8% (18/2,329, papillary thyroid microcarcinomas [PTMCs]) and was higher in the ITN-positive group than in the ITN-negative group (3.6% [4/111] vs. 0.6% [14/2,218], P=0.009). Among the 2,011 subjects who underwent both LDCT and thyroid US, all risks were higher (P<0.001) in the ITNpositive group than in the ITN-negative group: presence of thyroid nodule on US, 94.1% (95/101) vs. 48.6% (928/1,910); recommendation of FNA according to the American Thyroid Association guideline and Korean Thyroid Imaging Reporting and Data System guideline, 41.2% (42/101) vs. 2.4% (46/1,910) and 39.6% (40/101) vs. 1.9% (37/1,910), respectively.

CONCLUSION

Despite a higher risk of thyroid cancer in the LDCT ITN-positive group than in the ITN-negative group in a lung cancer screening population, all cancers were PTMCs. A heavy smoking history may not necessitate thorough screening US for thyroid incidentalomas.

Haemoptysis: An Uncommon Presentation in an Incidental Thyroid Nodule-A Case Report

Thyroid cancers invading the critical structures like trachea, oesophagus, recurrent laryngeal nerve and major vessels are uncommon. Even though uncommon, patients with large thyroid lesion (> 4 cm) or aggressive histology can present with features of invasion. Careful evaluation and appropriate surgical management is needed for optimal outcome. This case is presented to make our otolaryngology-head and neck surgeons aware of such unique situation where an incidental thyroid nodule presenting as haemoptysis due to tracheal invasion.

Management of Incidentalomas

Incidental findings are common in the evaluation of surgical patients. Understanding the appropriate assessment and management of these frequent occurrences is important for the provision of comprehensive quality care. This review details the epidemiology, considerations, and recommendations for management of common incidental manifestations in surgical patients, including Meckel diverticulum, adrenal incidentaloma, thyroid nodule, solitary pulmonary nodule, small bowel intussusception, gallstones, and incidental appendectomy.

Incidentally Discovered Thyroid Nodules by Routine Magnetic Resonance Imaging of the Cervical Spine: Incidence and Clinical Significance

OBJECTIVE

The aim of our study was to present the prevalence of thyroid nodules we incidentally discovered by routine Magnetic Resonance Imaging (MRI) of the cervical spine, to evaluate their clinical significance, and to discuss the current clinical approach to incidental thyroid nodules.

METHODS

We retrospectively evaluated the cervical spinal MRI studies of 512 patients. Thyroid glands were evaluated for morphologic and signal characteristics and examined for the presence of nodule(s). The nodules with a maximum diameter of 5 mm or more were taken into analysis.

RESULTS

Of 512 MRI studies, 254 revealed incidental thyroid nodule(s) (49.6%). The mean maximum nodule diameter was 7.48±2.92 mm. Thirty-eight of 254 incidental thyroid nodules were radiologically reported, 35 reported nodules were evaluated by US, and 22 were further analyzed by fine needle aspiration cytology. The final diagnosis of 11 aspirated nodules was an adenomatous nodule, whereas 3 were papillary thyroid carcinoma. One of the patients with papillary thyroid carcinoma was a 32-year-old man with a nodule with a maximum diameter of 7 mm.

CONCLUSION

Incidental thyroid nodule is a frequent non-spinal lesion detected by routine cervical spinal MRI. The 3-tiered system which is recommended in the clinical approach to incidental thyroid nodules may miss some clinically significant thyroid nodules. We suggest the criteria of this system to be re-evaluated and modified if necessary. In addition, we would like to emphasize the need for a guideline for radiologists for reporting incidental thyroid nodules on MRI on the basis of a standard clinical approach.

Evaluation of Incidental Thyroid Nodules in Cancer Patients

OBJECTIVE

Frequency of thyroid cancer in incidental thyroid nodules identified by imaging techniques in cancer patients is higher than that in the normal population. In the retrospective study, we have both investigated the incidence of thyroid cancer in incidentally identified nodules and compared the imaging techniques to determine whether there is any difference between them in detection of malign nodules.

METHODS

A total of 7319 patients who underwent thyroid fine-needle aspiration biopsy (FNAB) were included in the study. The data of 174 patients who had previously been diagnosed with a hematologic or solid malignancy prior to the FNAB procedure and had incidentally identified thyroid nodules were evaluated retrospectively.

RESULTS

Eighty-six (49.5%) of the incidental nodules were identified with ultrasonography (USG), 62 (35.6%) with positron emission tomography (PET) or PET/computed tomography (PET/CT), and 26 (14.9%) with CT. As a result of thyroidectomy, papillary carcinoma was identified in 8 (4.6%) patients, and metastasis to the thyroid of a primary cancer was found in 3 (1.7%) patients. While the papillary carcinoma proportion in the nodules identified by USG was 3.4%, PET/CT was 8.9%. A cut-off maximal standardized uptake value of 11.6 in PET/CT indicated malignancy achieving a sensitivity of 83.3% and a specificity of 91.1%.

CONCLUSION

Whether the nodule in the incidental thyroid nodules of cancer patients is identified using USG or PET/CT, the risk of thyroid cancer is similar. However, cancer risk is higher in the event of a higher focal uptake in the nodules identified by PET/CT.

Thyroid computed tomography imaging: pictorial review of variable pathologies

Abstract

Focal and diffuse thyroid abnormalities are commonly encountered during the interpretation of computed tomography (CT) exams performed for various clinical purposes. These findings can often lead to a diagnostic dilemma, as the CT reflects the nonspecific appearances. Ultrasound (US) examination has a superior spatial resolution and is considered the modality of choice for thyroid evaluation. Nevertheless, CT detects incidental thyroid nodules (ITNs) and plays an important role in the evaluation of thyroid cancer.

In this pictorial review, we cover a wide spectrum of common and uncommon, incidental and non-incidental thyroid findings from CT scans. We also discuss the most common incidental thyroid findings, best practices for their evaluation, and recommendations for their management. In addition, we explore the role of imaging in the assessment of thyroid carcinoma (before and after treatment) and preoperative thyroid goiter, as well as localization of ectopic and congenital thyroid tissue.

Teaching Points

• Thyroid disorders tend to have non-specific CT appearances.

• ITNs are common on neck CT.

• ITN management depends on nodule size, age, health status, lymphadenopathy, and invasion.

• CT is used in assessment of cancer extension, mass effect, invasion, and recurrence.

• CT plays a role in preoperative planning in patients with symptomatic goiter.

Evaluation of thyroid incidentaloma

Thyroid nodules are an extremely common endocrine disorder with a generally accepted prevalence of around 4% to 7%. Incidental thyroid nodules are typically nonpalpable thyroid nodules found during radiographic evaluation for a non-thyroid-related issue (eg, computed tomographic scan, positron emission tomography scan, carotid duplex). Incidental thyroid nodules are contributing to but are not the sole reason for the rising incidence of thyroid cancer in the Unites States and other developed nations.