Cowden syndrome (CS) is a rare dominantly inherited multisystem disorder, characterized by an extraordinary malignant potential. In 80% of cases, the human tumor suppressor gene phosphatase and tensin homolog (PTEN) is mutated. We present a case of a 17-year-old boy with genetically confirmed CS and Graves' disease (GD). At the age of 15, he presented with intention tremor, palpitations, and marked anxiety. On examination, he had macrocephaly, coarse facies, slight prognathism, facial trichilemmomas, abdominal keratoses, leg hemangioma, and a diffusely enlarged thyroid gland. He started antithyroid drug (ATD) therapy with methimazole and, after a 2-year treatment period without achieving a remission status, a total thyroidectomy was performed. Diagnosis and management of CS should be multidisciplinary. Thyroid disease is frequent, but its management has yet to be fully defined. The authors present a case report of a pediatric patient with CS and GD and discuss treatment options.

Objective:The optimal time for a neck ultrasound (US) in the follow-up of papillary thyroid cancer (PTC) after the first year is undetermined. We aimed to verify the utility of routine neck US in the surveillance of patients diagnosed with low-and intermediate-risk PTC with no evidence of disease at the one-year assessment. Materials and methods: We conducted a retrospective longitudinal study of patients with low-and intermediate-risk PTC with normal neck US, unstimulated serum thyroglobulin (Tg) < 1 ng/mL and negative anti-Tg antibodies at the one-year follow-up. Patients were divided into group 1 [undetectable Tg (<0.20 ng/mL)] and group 2 [detectable Tg but < 1 ng/mL]. The negative predictive value (NPV) of the one-year unstimulated Tg at the five-year and last follow-up visits was calculated. Results: We included n = 88 patients in group 1 and n = 8 patients in group 2. No patient from group 1 presented suspicious US findings at the five-year evaluation [NPV: 100.0% (95% confidence interval (CI): 95.5%-100.0%)], and at the last visit, only one patient had developed a lymph node classified as suspicious [NPV: 98.8% (95% CI: 93.2%-100.0%); mean follow-up: 6.7 years]. In group 2, two patients' USs presented suspicious findings at the five-year evaluation [NPV: 75.0% (95% CI: 34.9%-96.8%)]. At the last visit, only one patient persisted with suspicious findings in the US [NPV: 87.5% (95% CI: 47.4%-99.7%); mean follow-up: 6.5 years]. Conclusion: Low-and intermediaterisk PTC with an excellent response to treatment at the one-year assessment can be safely monitored with regular unstimulated Tg assessments. Conclusions should not be drawn for Tg levels between 0.20-0.99 ng/mL.