Background: Pediatric papillary thyroid carcinoma (PTC) is clinically and biologically distinct from adult PTC. We sequenced a cohort of clinically-annotated pediatric PTC cases enriched for high-risk tumors to identify genetic alterations of relevance for diagnosis and therapy. Methods: Tumor DNA and RNA were extracted from FFPE tissue and subjected to next generation sequencing (NGS) library preparation using a custom 124 gene hybridization capture panel and the 75 gene Archer Oncology Research Panel, respectively. NGS libraries were sequenced on an Illumina MiSeq. Results: Thirty-six pediatric PTC cases were analyzed. Metastases were frequently observed to cervical lymph nodes (29/36, 81%), with pulmonary metastases less commonly found (10/36, 28%). Relapsed or refractory disease occurred in 18 patients (18/36, 50%). DNA sequencing revealed targetable mutations in 8 of 31 tumors tested (26%), most commonly BRAF p.V600E (n=6). RNA sequencing identified targetable fusions in 13 of 25 tumors tested (52%): RET (n=8), NTRK3 (n=4), and BRAF. Mutually-exclusive targetable alterations were discovered in 15 of the 20 tumors (75%) with both DNA and RNA analyzed. Fusion positive PTC was associated with multifocal disease, higher tumor staging, and higher American Thyroid Association (ATA) risk levels. Both BRAF V600E mutations and gene fusions were correlated with the presence of cervical metastases. Conclusions: Targetable alterations were identified in 75% of pediatric PTC cases with both DNA and RNA evaluated. Inclusion of RNA sequencing for detection of fusion genes is critical for evaluation of these tumors. Patients with fusion positive tumors were more likely to have features of high-risk disease.
Recurrent respiratory papillomatosis (RRP) is a benign tumor of the respiratory tract associated with human papillomavirus types 6 and 11. Patients undergo multiple surgical debridements for management of rapidly growing papilloma. Adjuvant treatment options for management of RRP in children are often ineffective and do not decrease the need for repeated surgical debridement. We report on three patients initially treated with 10 mg/kg systemic bevacizumab every 4 weeks. All patients had improvement in voice and reduced need for surgical debridement. The interval between bevacizumab doses was gradually increased to every 8-12 weeks. Adverse events included mild proteinuria and self-resolving epistaxis.