Diagnostic Performance of Core Needle Biopsy for Characterizing Thyroidectomy Bed Lesions

Abstract

Objective: Thyroidectomy bed lesions frequently show suspicious ultrasound (US) features after thyroid surgery. Fine-needle aspiration (FNA) may not provide definitive pathological information about the lesions. Although core-needle biopsy (CNB) has excellent diagnostic performance in characterizing suspicious thyroid nodules, no published studies have evaluated the performance of CNB specifically for thyroidectomy bed lesions. Therefore, we aimed to evaluate the diagnostic performance and safety of CNB for characterizing thyroidectomy bed lesions.

Materials and methods: A total of 124 thyroidectomy bed lesions in 113 patients (79 female and 34 male; age, 23-85 years) who underwent US-guided CNB between December 2008 and December 2020 were included. We reviewed the US imaging features of the target lesions and the histories of previous biopsies. The pathologic results, diagnostic performance for malignancy, and complications of CNB were analyzed.

Results: All samples (100%) obtained by CNB were adequate for pathological analysis. Pathological analysis revealed inconclusive results in two lesions (1.6%). According to the reference standard, 50 lesions were ultimately malignant (40.3%), and 72 were benign (58.1%), excluding the two inconclusive lesions. The performance of CNB for diagnosing malignant thyroidectomy bed lesions in the 122 lesions had a sensitivity of 98.0% (49/50), a specificity of 100% (72/72), positive predictive value of 100% (49/49), and negative predictive value of 98.6% (72/73). Eleven lesions were referred for CNB after prior inconclusive FNA results in thyroidectomy bed lesions, for all of which CNB yielded correct conclusive pathologic diagnoses. According to the pathological analysis of CNB, there were various benign lesions (58.9%, 73/124) besides recurrence, including benign postoperative lesions other than suture granuloma (32.3%, 40/124), suture granuloma (15.3%, 19/124), remnant thyroid tissue (5.6%, 7/124), parathyroid lesions (4%, 5/124), and abscesses (1.6%, 2/124). No major or minor complications were associated with the CNB procedure.

Conclusion: US-guided CNB is accurate and safe for characterizing thyroidectomy bed lesions.

Keywords: Core-needle biopsy; Fine-needle aspiration; Thyroid; Thyroid cancer; Thyroidectomy; Ultrasonography.

Fig. 1. Flow chart of the study.

The numbers are number of lesions.

Fig. 2. A 57-year-old male with a history of total thyroidectomy due to papillary thyroid cancer 2 years previous.

A. Axial gray-scale view shows a 1.1 cm hypoechoic mass (arrowheads) at the left thyroidectomy bed. There was an inner focal macrocalcification. B. Color Doppler image shows no definite internal vascularity. The sonographic impression of the lesion was malignant (recurrent thyroid cancer). The pathologic result of the core-needle biopsy was a recurrence of papillary thyroid cancer.

Fig. 3. A 37-year-old female with a history of total thyroidectomy due to papillary thyroid cancer 3 years previous.

A, B. Axial (A) and sagittal (B) gray-scale views show a 1.1 cm hypoechoic mass (arrowheads) with inner-paired microcalcifications (arrow) in the right thyroidectomy bed. The sonographic impression of the lesion was benign (suture granuloma). The pathologic result of the core-needle biopsy was suture granuloma.

Fig. 4. A 58-year-old female with a history of total thyroidectomy due to papillary thyroid cancer 8 years previous.

A. Axial gray-scale view shows a 0.8 cm well-defined ovoid-shaped hypoechoic lesion at the right thyroidectomy operation bed. B. Color Doppler image shows increased internal vascularity of the mass (arrowhead). The sonographic impression of the lesion was benign (remnant thyroid tissue). The pathologic result of the core-needle biopsy was remnant thyroid tissue.

Fig. 5. A 52-year-old female with a history of right lobectomy due to papillary thyroid cancer 12 years previous.

The lesion was surgically confirmed as parathyroid adenoma. A-C. Axial gray-scale (A), axial color Doppler (B), and saggital gray-scale (C) ultrasound views show a 1.4 cm well-defined cystic and solid hypoechoic mass (arrowheads) at the right thyroidectomy bed. The sonographic impression of the lesion was malignant (recurrent thyroid cancer). The pathologic result of the core-needle biopsy was a parathyroid lesion.