ESPE Abstracts

Introduction: Thyroid carcinoma in pediatric and young adult population presents contradictory features: it has higher rates of multifocal disease, local and distant metastasis and reccurence compared to the adult population, yet the 5-year survival rate is 98%. The rising incidence seen recently cannot be entirely explained by overdiagnosis, as increasing rates of advanced-stage disease are also observed. The rise consists primarily of papillary thyroid carcinomas (PTC), the most prevalent type also encountered in adulthood, but with distinct histomolecular features (frequent high-risk subtypes and gene fusions). We present the cases of 3 girls without known risk factors, whom were incidentally diagnosed with multifocal, aggressive variants of PTC and had completely different outcomes.

Case presentations: First patient, aged 18, presented for obesity. Ultrasound examination identified a suspicious nodule that was biopsied (Bethesda IV). She underwent total thyroidectomy (TT) with central and right laterocervical lymph nodes dissection and radioactive iodine therapy (RAI). Histopatological exam revealed diffuse, multifocal, tall-cell PTC with lymphovascular, perineural, perivascular invasion and multiple metastatic lympadenopathies with extranodal extension. Bilateral reccurent laterocervical disease ensued. The patient underwent right laterocervical lymphadenectomy, left dissection being impaired by local fibrosis. Latest cervical ultrasound revealed progression of left laterocervical lymphadenopathies and hormonal dosages indicated increased serum thyroglobulin (90.77ng/ml). Subsequently, a second cure of RAI is scheduled. Second patient, aged 14, presented for secondary amenorrhea. Being known with nontoxic goitre, ultrasound examination was performed. A nodule with two-fold increase in a month’s time was observed. Moreover, an ipsilateral, suspicious lymphadenopathy was identified. FNA cytology identified a Bethesda V lesion. TT with central and unilateral laterocervical dissection was undergone. Pathology examination determined a multifocal, unencapsulated, diffuse sclerosing lesion, with lymphovascular, perivascular and perineural invasion and metastatic lympadenopathies, some with extranodal extension. Immunohistochemistry and RAI are envisioned. Third patient, aged 20, presented for subclinical hyperthyroidism. Ultrasound showed a suspicious nodule that was biopsied (Bethesda V). TT with central lymphodissection and RAI were carried out. Pathology examination determined a multifocal, unencapsulated, diffuse sclerosing lesion, with both follicular and papillary patterns and lymphovascular invasion. One year later, there was a slight increase in unstimulated thyroglobulin and whole-body scintigraphy identified remnant thyroid tissue on the thyroglossal path, indicating the need for repeated RAI.

Conclusions: Our case series aims to shed light on the unpredictability of PTC in pediatric and young adult population and the need of specific guidelines for these age groups, not based only upon the experience treating adults.