ESPE Abstracts

Introduction: Papillary thyroid carcinoma (PTC) in the pediatric and young adult population presents contradictory features: it shows higher rates of multifocal disease, local and distant metastasis, and recurrence compared to adults, yet the overall 5-year survival rate remains exceptionally high at 98-100%. In children, RET/PTC rearrangements are the major somatic genetic alterations that drive the formation of PTC. On the other hand, mutations in BRAF are commonly seen in adults with thyroid carcinoma and can have therapeutic and prognostic implications. The BRAF V600E mutation is seen in approximately 40% of cases of PTC, and is associated with extrathyroidal tumor extension (ETE), higher recurrence rate, and disease related mortality.

Case report: An 18-year-old girl presented for evaluation of severe obesity and was incidentally diagnosed with PTC and metastatic lymphadenopathies. Histopathological examination revealed diffuse multifocal papillary carcinoma with a high-cell component, lymphovascular, perineural, and perivascular invasion, as well as multiple metastatic lymphadenopathies with extranodal extension. She underwent a total thyroidectomy with central and right lateral neck dissection, followed by radioiodine therapy. The patient later experienced a relapse in the lateral cervical lymph nodes and underwent recurrent right lateral cervical lymphadenectomy. Serum thyroglobulin remained increased and ultrasound detected isostructural adenopathies in the laterocervical lymph nodes. Thus, a second cure of radioiodine was administered. At follow-up, thyroglobulin levels remained highly elevated, ultrasound detected multiple metastatic lymph nodes, but I¹³¹ whole-body scan showed no uptake. Therefore, a PET-CT is envisioned. Genetic testing revealed the presence of V600E BRAF mutation.

Conclusion: The presence of BRAF V600E mutation has been associated with much more aggressive forms of PTC, especially in adults. However, BRAF mutations may provide therapeutic targets for patients with more aggressive thyroid carcinoma. It is important to understand the various molecular alterations, as they have therapeutic impacts. This case highlights the importance of testing for molecular targets in the treatment of thyroid cancer that has progressed on standard therapy.