The loss of the thin lucent rim around a thyroid lesion is a significant finding on ultrasound. See how the mass blends in with the surrounding parenchyma just below the "A" of the caliper? It is a good indication for FNA, do not ignore this finding.

This was a confirmed papillary carcinoma thyroid.

Increasing size is an absolute indicator for sampling in a thyroid lesion regardless of the characteristics of the lesion.