Benign and Malignant Thyroid Nodules: US Differentiation—Multicenter Retrospective Study

Abstract

Shape, margin, echogenicity, and presence of calcification are helpful criteria for the discrimination of malignant from benign nodules; the diagnostic accuracy of US criteria is dependent on tumor size.

Thyroid nodules and evaluation of thyroid cancer risk

“…However, the great majority of thyroid nodules are impalpable and asymptomatic with an estimated prevalence of 20–76% in the general population 1 . These small nodules are increasingly detected by neck ultrasound and parallel the rising incidence of small differentiated thyroid cancer over the last two decades 12 .…”

“…The presenting clinical problems include hyperthyroidism, pain (often due to haemorrhage into a cyst) and compressive symptoms (due to a multinodular goitre). However, the clinical priority in the initial management of a thyroid nodule is to evaluate its thyroid cancer risk to guide decision regarding thyroidectomy 12 . Thyroid cancer occurs in 5–15% of nodules 2 .…”

“…Microcalcifications and abnormal cervical lymph nodes probably have the highest predictive values for thyroid cancer (up to 94% and 100% respectively), although their sensitivity is generally low (26% and 5% respectively) 2 , 12 – 15 . Microcalcifications seen as punctate echogenicities are due to calcified psammoma bodies typical of papillary thyroid cancer 12 .…”

“…They can be difficult to distinguish from colloid but the presence of comet‐tail artifacts associated with colloid crystals may be helpful 2 , 13 . The association of macrocalcifications with thyroid cancer is less consistent 8 , 11 , 12 , 15 . However, recent data suggest that coarse calcifications and disrupted peripheral or “eggshell” calcifications are also markers of increased cancer risk 4 , 11 , 12 .…”

“…The cancer risk of a predominantly cystic non‐solitary nodule without calcifications is less than 2% and completely cystic nodules are rarely malignant 8 . The “spongiform” colloid nodule containing aggregated multiple microcystic components (involving more than 50% of nodule volume) is also unlikely to be malignant 2 , 12 .…”