Most Thyroid Cancers Detected by Sonography Lack Intranodular Vascularity on Color Doppler Imaging: Review of the Literature and Sonographic-Pathologic Correlations for 698 Thyroid Neoplasms.

OBJECTIVES: This study investigated the controversy of whether hypervascularity on color Doppler sonography correlates with thyroid malignancy by reviewing the literature and sonographic-pathologic correlation.

METHODS: Over a 20-year period, 698 thyroid nodules had color Doppler and histopathologic data. Intranodular vascularity was graded 0 to 3+, and histopathologic findings were recorded.

RESULTS: The data were collected from 698 patients (557 women and 141 men) with a mean age of 48 years (range, 16-87 years). Of the 698 neoplasms, 425 were malignant (mean size, 1.7 cm; range, 0.4-9 cm; 150 ≤1 cm), and 273 were benign. The carcinomas included 391 papillary, 12 Hürthle cell, 9 medullary, 6 follicular, 5 poorly differentiated, and 2 anaplastic. The grading of intranodular vascularity was 0 in 63.3%, 1+ in 12.9%, 2+ in 6.6%, and 3+ in 17.4%. Among thyroid carcinomas, follicular carcinoma and the encapsulated subtype of the follicular variant of papillary carcinoma had significantly higher intranodular vascularity than the rest (P < .0001). Benign neoplasms included 226 follicular adenoma/adenomatoid nodules (mean size, 3.2 cm; range, 1.2-8.0 cm), 42 Hürthle cell adenoma/adenomatoid nodules (mean size, 2.6 cm; range, 0.8-5.5 cm), and 5 hyalinizing trabecular adenomas (mean size, 2.4 cm; range, 0.6-6.0 cm; 4 ≤1 cm). The grading of intranodular vascularity was 0 in 6.9%, 1+ in 12.1%, 2+ in 2.6%, and 3+ in 78.4%. Intranodular hypervascularity was associated with adenoma/adenomatoid thyroid nodules, whereas a lack of vascularity was related to thyroid carcinomas (P < .0001).

CONCLUSIONS: Most sonographically detected thyroid cancers lack intranodular vascularity, and most hypervascular thyroid nodules are adenoma/adenomatoid nodules, the encapsulated subtype of the follicular variant of papillary carcinoma, or follicular carcinomas.