Objective: The purpose of this article is to characterize sonographic features of differentiated thyroid cancer recurrence in the thyroidectomy bed.
Materials and methods: Patients referred for biopsy of thyroidectomy bed lesions between February 2006 and December 2009 were identified. Patient data and gray-scale and color Doppler features were recorded.
Results: Results of ultrasound-guided biopsies of 30 nodules in 27 patients were reviewed. Twenty-five lesions yielded diagnostic findings, including 22 recurrences in 19 patients and three benign lesions in three patients. Five biopsies were nondiagnostic. Among the 22 recurrences, 21 (95%) were hypoechoic and one (5%) was mixed hypoechoic and hyperechoic on gray-scale imaging. On Doppler imaging, 100% of recurrences had detectable vascularity. Eight lesions (36%) had microcalcifications, and five (23%) had coarse calcifications; the average long-axis dimension was 1.5 cm. Of the five nondiagnostic lesions, four (80%) were hypoechoic, one (20%) was isoechoic, one (20%) had microcalcifications, none had coarse calcifications, and two (40%) had vascularity; the average long-axis dimension was 0.6 cm. Of the negative lesions, three (100%) were hypoechoic, two (66%) had vascularity, and two (66%) had coarse calcifications. No microcalcifications were seen, and the average long-axis dimension was 2 cm. Serum thyroglobulin (Tg) or anti-Tg antibodies were elevated in 12 (63%) of 19 patients with recurrence (eight [42%] with elevated Tg levels and four [21%] with elevated anti-Tg antibody levels).
Conclusion: An ultrasound finding of a hypoechoic thyroidectomy bed lesion with internal vascularity and size greater than 6 mm is highly sensitive in predicting recurrence. Serum Tg levels were less sensitive than ultrasound in detection of recurrence in the thyroidectomy bed.