Amy Liebeskind MD, Presenter: Nothing to Disclose

Andrew Sikora MD, Abstract Co-Author: Nothing to Disclose

Arnold Komisar MD, Abstract Co-Author: Nothing to Disclose

Daniel Slavit MD, Abstract Co-Author: Nothing to Disclose

Karen Fried MD, Abstract Co-Author: Nothing to Disclose

Thyroid nodules are identified relatively frequently on radiologic studies performed for non-thyroid indications. The purpose of this study was to assess the rate of malignancy in thyroid nodules discovered incidentally on MRI, CT, or US imaging.

All thyroid ultrasound and FNA procedures from 4/1/03 to 9/30/03 were retrospectively reviewed. Study indications were categorized as incidental (thyroid nodules found on MRI, CT, or US imaging performed for non-thyroid indications) or non-incidental (abnormal physical examination or laboratory values; signs or symptoms suspicious for thyroid disease). Rates of suspicious or malignant results in patients with incidentally-discovered nodules who underwent FNA were compared with rates in patients with non-incidental thyroid abnormalities using Fisher’s exact test. Logistic regression analysis was performed to assess potential contributions of patient and nodule characteristics to differences in malignancy rates between the study groups.

Of 225 thyroid sonograms, 35 (16%) studies were performed for incidentally discovered thyroid nodules (incidental group), and 190 (84%) examinations were performed for evaluation of non-incidental thyroid abnormalities (non-incidental group). A total of 21 (60%) patients in the incidental group and 90 (47%) patients in the non-incidental group underwent FNA. The rate of suspicious or malignant FNA results in biopsied nodules in the incidental group was 35%, compared to 7% in the non-incidental group (p =0.001). Patient sex, multiplicity of nodules, nodule size, nodule echotexture, and presence of calcifications did not differ significantly between the two groups. The mean age of patients in the incidental group was significantly higher (62 vs 51 years, p=0.0007). However, logistic regression demonstrated that the only significant predictor of benign or suspicious/malignant FNA was incidental vs. non-incidental status.

The current study identifies an unexpectedly high rate of malignancy in incidentally-discovered thyroid nodules, suggesting that follow up thyroid sonogram and, when indicated, FNA, may be appropriate management strategies for incidentally-discovered thyroid nodules.

Liebeskind, A, Sikora, A, Komisar, A, Slavit, D, Fried, K, Rates of Malignancy in Incidentally-Discovered Thyroid Nodules Evaluated with Sonography and Fine Needle Aspiration.  Radiological Society of North America 2004 Scientific Assembly and Annual Meeting, November 28 - December 3, 2004 ,Chicago IL. http://archive.rsna.org/2004/4405356.html