Thyroid Ultrasound > Nodule Management > Follow-up Recommendation


Follow-Up Recommendations

According to Moon WJ, et all (Radiology June 2008), US criteria for the discrimination of malignant from benign nodules are taller-than-wide shape, spiculated margin, marked hypoechogenicity, and the presence of microor macrocalcifications, of which the diagnostic accuracy may be dependent on tumor size; furthermore, isoechogenicity of the nodule in conjunction with a spongiform appearance are reliable US criteria for benign nodules. "Benign and Malignant Thyroid Nodules: US Differentiation - Multicenter Retrospective Study" by Moon WJ, et al.

 

Society of Radiologists in Ultrasound Consensus 2005 (table directly adapted) 

"Management of Thyroid Nodules Detected at US: Society of Radiologists in Ultrasound Consensus Conference Statement" by Frates MC, et al.

 

 

The American Thyroid Association Guidelines Taskforce 2006 (flowchart directly adapted) 

"Management Guidelines for Patients with Thyroid Nodules and Differentiated Thyroid Cancer" by Cooper DS, et al.

For a guide on incidental thyroid nodules, please refer to this excellent AJR Nov 2010 article (quoted): 

"Incidental Thyroid Nodules on Chest CT: Review of the Literature and Management Suggestions" by Ahmed, et al.

According to the most recent guidelines established by the NCCN (National Comprehensive Cancer Network) in 2009, solitary nodules measuring greater than 1 cm in diameter in patients with certain risk factors should be further evaluated with measurement of TSH levels, neck ultrasound, and FNA of nodules and clinically suspicious lymph nodes. Risk factors include age below 15 years and above 60 years, male sex, history of head and neck radiation, history of diseases associated with thyroid cancer (e.g., Gardner syndrome, Cowden syndrome, and Carney complex), and family history of thyroid cancer. Intranodular hypervascularity, irregular borders, and microcalcification seen on ultrasound are also important factors associated with malignancy. Nodules that are very firm, have exhibited a pattern of rapid growth, or are invading other neck structures should be considered for surgery after FNA. The NCCN also recommends that unsuspected nodules that measure less than 1 cm in patients without the aforementioned risk factors should be monitored and followed-up clinically as indicated and a neck ultrasound may be considered.

According to the literature, nodules measuring 1 cm or greater detected on CT or smaller nodules with worrisome CT features, such as calcifications or invasion of surrounding structures, should probably be referred for ultrasound evaluation and ultimately FNA biopsy.

However, there is still uncertainly in how to handle a small nodule of less than 1 cm detected incidentally on chest CT. At this point, given the limitations of CT, it is probably prudent to report all thyroid nodules detected on CT. However, it is probably not reasonable to advise a follow-up ultrasound examination in every patient and it should be left up to the clinician who has full access to clinical information and the medical history of these patients. 

Metabolically active thyroid nodules detected on fused positron emission tomography and computed tomography (PET-CT) are associated with a 1 in 3 chance of malignancy and should be further evaluated PET-CT may have a future role in reducing unnecessary surgery in patients with indeterminate cytology because of its high negative predictive value.



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