Abstract

Background: Differentiated thyroid carcinoma (DTC) in children is rare but has shown an increasing global incidence. Compared to adults, pediatric DTC exhibits higher rates of local invasion, lymph node metastasis, and distant metastasis. Nevertheless, overall survival is excellent, with a 10-year survival rate exceeding 98%. Surgery plays a pivotal role in treatment. In Vietnam, studies on pediatric DTC remain limited. Objectives: To describe the clinical and paraclinical characteristics, postoperative complications, and recurrence in children with D. Materials and Methods: A retrospective case series study was conducted on 31 pediatric patients with DTC who underwent surgery at Children’s Hospital 1 from January 2019 to June 2022. Results: The mean age was 12.2 ± 2.5 years, with the majority ≥ 10 years old (80.7%) and a female-to-male ratio of 2.5:1. The most common presentation was a neck mass (87.1%) and most patients were euthyroid. The majority had solitary thyroid nodules (mean size 29 mm) with highly suspicious ultrasound features; 87.5% were classified as TI-RADS 5. Preoperative FNA showed malignancy in 96.8% of cases, mainly Bethesda category VI. Total thyroidectomy was performed in 83.9% of patients, with adjuvant radioactive iodine therapy in 26 cases. Histopathology confirmed papillary thyroid carcinoma as the predominant type (97%), with local invasion in 42%, lymph node metastasis in 80%, and distant metastasis in 38.7% (predominantly lung). According to ATA 2015, most patients were classified as high risk (54.9%). Common complications included transient hoarseness (19.4%) and transient hypoparathyroidism (64.5%), while permanent hypoparathyroidism occurred in 9.7%. Transient hoarseness was significantly associated with male sex (p=0.04), recurrent laryngeal nerve invasion (p < 0.001), and gross lymph node invasion (p = 0.001). Transient hypoparathyroidism was strongly associated with the surgical method (p < 0.001). In patients undergoing total thyroidectomy, higher stimulated thyroglobulin (Tg) levels at 21 days postoperatively were significantly associated with an increased risk of distant metastasis (p = 0.045). Conclusions: Pediatric DTC typically presents after age 10 as a neck mass, exhibiting highly suspicious ultrasound features, predominantly papillary histology, frequent cervical lymph node metastasis, and high-risk classification. Regarding complications, transient hoarseness is significantly associated with male sex, recurrent laryngeal nerve invasion, and gross lymph node invasion, whereas transient hypoparathyroidism is strongly associated with total thyroidectomy. The rate of distant metastasis is high (predominantly pulmonary) and shows an increased risk associated with higher stimulated Tg levels at 21 days postoperatively.