Summary Endothelial receptor tyrosine kinases may play important roles in pathological vascular growth, particularly in tumours. In this study, immunohistochemistry was used to evaluate the expression of a novel endothelial receptor tyrosine kinase, Tie2/Tek, in the endothelium of vascular 'hotspots' in normal breast tissue (n = 10), benign breast lesions (n = 10) and in breast tumours (n = 123). Tie2 expression was detected in the endothelium of all breast tissues examined. However, the strongest expression of Tie-2 was seen in vascular 'hot spots' within the inflammatory infiltrate at the periphery of invasive tumours. Moreover, the proportion of Tie2-positive vessels (Tie2 counts/CD31 counts) was significantly higher in breast tumours than the proportion of Tie2-positive vessels in either normal breast tissue or benign breast lesions (P = 0.004 and 0.0001 respectively). These data are consistent with a role for Tie2 in tumour angiogenesis and demonstrate the potential use of Tie2 expression as a novel marker of the tumour vasculature.

Background The American Thyroid Association guidelines task force currently recommends definitive thyroidectomy or lobectomy after an indeterminate thyroid biopsy in children. This recommendation is based on evidence of a greater incidence and a higher risk of malignancy compared with adults in earlier pediatric studies. Such management may lead to overtreatment and unnecessary surgery for many children in the United States. Methods The objective of the current study was to re‐evaluate pediatric thyroid nodules and assess the overall percentages and malignancy rates for indeterminate thyroid biopsies in children. In total, 302 pediatric thyroid fine‐needle aspirations (FNAs) were analyzed retrospectively (2001‐2018). Distribution percentages and malignancy rates were calculated for each category of The Bethesda System for Reporting Thyroid Cytopathology (TBSRTC). Results Two indeterminate TBSRTC groups (atypia of undetermined significance/follicular lesion of undetermined significance and follicular neoplasm/suspicious for a follicular neoplasm) had much lower distribution percentages and malignancy rates compared with earlier pediatric series and American Thyroid Association guidelines. A meta‐analysis further supported these findings and demonstrated distinctly different malignancy rates for the indeterminate groups (atypia of undetermined significance/follicular lesion of undetermined significance, follicular neoplasm/suspicious for a follicular neoplasm, and suspicious for malignancy), suggesting the need for TBSRTC category‐specific management recommendations rather than a nondiscriminatory, up‐front surgical approach. Conclusions Adult patients with indeterminate preoperative thyroid cytopathology are followed by repeat biopsy and possibly molecular testing before undergoing definitive surgery. However, in children, the guidelines are considerably more aggressive and recommend definitive surgery after the first indeterminate thyroid biopsy. Here, the largest pediatric cohort to date with meta‐analysis is presented, and the authors propose a re‐evaluation of this up‐front approach to pediatric thyroid care.

A b s t r a c t Interpretation of soft tissue and bone lesions with fine-needle aspiration (

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