Fig. 1

a Lymph node enlargement in ipsilateral neck region II was found in a 31-year-old female one year after surgery for thyroid cancer, which was not clearly diagnosed by two biopsy in other hospitals. After CEUS evaluation, heterogeneous enhancement of lymph nodes was found, with enhancement area in the middle (indicated by the arrows). b For the same patient, needle biopsy was performed on the enhanced area under the guidance of CEUS, and the triangle arrow is needle biopsy. c Although the specimen was broken tissue and bloody fluid, the pathological examination showed papillary thyroid carcinoma metastasis, so it was a valid specimen