ESPE Abstracts

Follicular thyroid carcinoma (FTC) is a rare subtypes of thyroid cancer in children that consists of less than 10% of thyroid cancer. It has a wide range of clinical behaviors from indolent to widely metastasis. There are currently no evidence-based consensus or management guidelines for FTC in children. We describe the treatment challenges in a 9-year old girl with encapsulated angiovasive follicular thyroid carcinoma post right hemithyroidectomy with an enlarged left submandibular lymph node. The risk stratification of FTC is different from the American Thyroid Association Guidelines paediatrics stratification (2015) for papillary thyroid carcinoma (PTC). The risk of FTC depends on the degree of invasion. In general, vascular invasion of more than 4 vessels are considered high risk. FTC in children are more likely associated with bilateral disease with higher risk of metastasis. However, unlike PTC, FTC most often metastasizes to the lungs but rarely metastasizes to lypmh nodes. It is important to also perform genetic testing in patient with FTC. As our patient had 6 foci of vascular invasion with a contralateral enlarged lymph node, we discussed with family on different treatment options and recommended completion total thyroidectomy with fine needle aspiration cytology (FNAC) of left post submandibular lymph node. Histology showed no malignancy of the left thyroid and the lymph node FNAC showed reactive lymphadenopathy with no evidence of malignancy. Subsequently she underwent thyroxine withdrawal and ablative radioactive iodine therapy (RAI) to eradicate residual tumor or metastasis. BRAF mutation came back to be negative. As the tumour falls into intermediate risk group. We will monitor her blood for thyroid function, thyroglobulin and anti-TG every 3 months and perform another stimulated thyroglobulin and a low dose I131 whole body scan around 9 months post RAI with thyroxine withdrawal. Ultrasound neck surveillance will be performed yearly.