Treatment with TRIAC in pediatric patients with MCT8

Monocarboxylate transporters (MCTs) allow the cellular entry of thyroid hormones, especially into the central nervous system (CNS), where they are crucial for neurodevelopment. MCT8 deficiency results in the combination of hypothyroidism in the CNS and peripheral hyperthyroidism, characterized by elevated T3 levels. The only treatment currently available is 3,3',5-triiodothyroacetic acid (TRIAC), a thyroid hormone analogue aimed at improving peripheral thyrotoxicosis and preventing the progression of neurological impairment. Here we assess the clinical, imaging, biochemical, and genetic characteristics of 4 patients with MCT8 deficiency who have received TRIAC to date, the doses used, and the response to treatment.

Rare tumors in pediatrics. First report in Argentina

Introduction

Collaborative clinical trials have enlarged the knowledge base about pediatric tumors; however, this is not the case for rare tumors (RT).

Objective

To describe the prevalence, clinical characteristics, and course of RT in pediatric patients diagnosed at Hospital Garrahan.

Material and methods

Descriptive, retrospective study of patients aged 0-18 years diagnosed with a RT and admitted between January 2007 and December 2017.

Results

Out of 1657 patients diagnosed with solid tumors, 164 (9.9 %) were RT; 71.95 % (118) of patients were younger than 14 years and 81.7 % (130) were males. In order of frequency, RT were thyroid carcinoma (60), adrenal carcinoma (14), lung tumors (14), melanoma (13), salivary gland cancer (11), gastrointestinal tumors (8), non-germ cell gonadal tumors (7), pancreatic tumors (7), renal carcinomas (6), nasopharyngeal carcinomas (5), pheochromocytoma and paraganglioma (5), and thymic carcinoma in 1 patient. Treatment depended on tumor type and stage. The median follow-up was 34.9 months (range: 1-128.5 months); 133 patients (78.7 %) are alive and only 10 patients (6 %) were lost-to-follow-up.

Conclusion

The prevalence of RT was 9.9 %. Twenty-seven percent occurred in adolescents. The most frequent tumors included thyroid carcinoma, adrenal carcinoma, and melanoma. Treatment and course varied based on tumor histology. Predisposing molecular alterations were found in 5.3 % of patients; 3.5 % had a history of cancer.

Diagnosis and management of Intratyroid Ectopic Thymus

INTRODUCTION

Intrathyroidal ectopic thymus (IET) is a rare benign condition caused by the aberrant thymic migra tion during embryogenesis. It is usually incidentally diagnosed as a thyroid nodule.

OBJECTIVE

To report the intrathyroidal location of ectopic thymic tissue and to describe the ultrasound findings in children.

PATIENTS AND METHOD

Retrospective descriptive review of the medical charts and thyroid ultrasound studies of children with nodular images in the thyroid gland, in a third level national pediatric hospital, from January 2010 to August 2017. Solid hypoecogenic intrathyroid lesions with multiple linear tracts or hyperechogenic points that did not change their characteristics during fo llow-up were considered intrathyroidal thymos. The ultrasound follow-up was performed every 4-6 months. The ultrasound characteristics of the lesions (location, laterality, size and shape), the indi cation of the ultrasound scan and the follow-up time were analyzed.

RESULTS

Of 147 patients with thyroid nodules, we identified 12 children with lesions suggestive of an IET (8.1%). The mean age at diagnosis was 3.9 years (range 0-8). It was an incidental finding in all cases. Imaging findings were unilateral in eight patients and bilateral in four patients. All lesions were located in the mid and/or posterior portion of the gland. We adopted a watch-and-wait approach with ultrasound follow-up (mean 2.2 years; range 0.83-4) in all patients except in a 7-year-old boy who presented uncertain findings and underwent surgery, confirming IET in the pathological study.

CONCLUSIONS

Thymic inclu sions in the thyroid gland are a rare but increasingly frequent finding, possibly related to the increased use of ultrasound studies. Pediatricians and radiologists should be aware of this entity to differentiate it from other thyroid lesions, avoiding unnecessary studies and/or treatments in these patients.

[Response to lenvatinib in a pediatric patient with respiratory failure associated with papillary thyroid carcinoma]

Papillary thyroid cancer is the most common thyroid tumor in childhood. In advanced stages, it can present with respiratory failure. The treatment of choice is total thyroidectomy and radioactive iodine. In cases of unresectable tumors, therapy with multikinase inhibitors should be considered. A 10-year-old girl was referred for progressive respiratory failure. A diagnosis of papillary thyroid cancer with pulmonary metastases was made. Due to the presence of an unresectable tumor not subject to surgery, the compassionate use of lenvatinib was indicated, showing a rapid and favorable clinical response with resolution of respiratory failure on the ninth day. Early diagnosis of papillary thyroid cancer prevents severe respiratory morbidity caused by late diagnoses. The use of lenvatinib should be considered as a previous step towards first-line therapies (surgery and radioactive iodine) in cases with great local and distant involvement.

MON-453 Dramatic Clinical Response to Lenvatinib in a Pediatric Patient with Advanced Metastatic Papillary Thyroid Carcinoma

Introduction: Papillary thyroid cancer (PTC) is the most common thyroid tumor in childhood. Most patients are referred with locally advanced and/or distant disease at the time of diagnosis. Whenever possible, these patients should be offered total thyroidectomy and radioiodine remnant ablation; however, this approach is not always feasible, rendering these tumors unresectable. These critical cases could benefit from neoadjuvant treatment with multikinase inhibitors (MKI) so that standard treatment can be performed. Lenvatinib is an MKI recently approved in many countries throughout the world for the treatment of radioiodine refractory adult differentiated thyroid cancer. Only few pediatric cases have been reported. Case report: A 10-year-old female patient with locally advanced PTC and metastasis to the lungs, who required 3 liters of oxygen due to respiratory failure caused by bilateral miliary lung disease, mistakenly treated as tuberculosis two months previously and referred to our Hospital. A large thyroid mass adhered to deep tissues was confirmed on CT scan, showing a large heterogeneous neck mass with multiple microcalcifications associated with multiple lymph nodes. Both lungs had multiple micro-nodular disease with interstitial involvement. Total thyroidectomy together with lymph-node dissection was planned, but extensive local infiltration made the lesion unresectable and surgery was limited to a thyroid biopsy. The patient required respiratory assistance. Histopathology confirmed the presence of a PTC (diffuse sclerosing variant) with a RET-PTC3 oncogene rearrangement. Eight days after surgery the patient was critical and we decided to indicate the compassionate use of Lenvatinib. The patient was started on oral lenvatinib at a dose of 14 mg daily (14 mg/m/day). Three days later, she clinically improved and nine days post-lenvatinib initiation, the patient was discharged from hospital without need for oxygen therapy. Lab studies showed a rise in thyroglobulin levels in the first month of treatment followed by a significant drop. All Lung Function Test parameters significantly improved. The patient initially had severe restrictive breathing and due to the resting dyspnea with hypoxemia she could not perform the walking test. Two months after treatment onset she could walk 360 meters in six minutes with 96% oxygen saturation. After 4 months on Lenvatinib, imaging studies showed a stable thyroid mass while the pulmonary nodules appeared stable to slightly smaller without evidence of new or progressive disease. Conclusion: On lenvatinib treatment, our patient showed significant clinical improvement, arrest of disease progression, and stable disease on imaging studies. This case shows that lenvatinib may be a beneficial option for children with advanced PTC not amenable to surgery/RAI treatment and may be used as a bridge to these first-line therapies.

[Muscle weakness with hypokalemia and hyperthyroidism in an adolescent with Down syndrome]

Acute hypokalemic paralysis is a rare cause of acute weakness. Thyrotoxic periodic paralysis (TPP) is an unusual complication of hyperthyroidism. It is characterized by sudden onset of hypokalemia condition resulting from a shift of potassium into cells and paralysis that primarily affects the lower extremities. Failure to recognize TPP may lead to improper management. Treatment of TPP includes replacing potassium rapidly, using nonselective beta-blockers and correcting the underlying hyperthyroidism as soon as possible. TPP is curable once euthyroid state is achieved. We describe a 13-year-old male with Down syndrome who presented with acute onset of lower extremity weakness secondary to acute hypokalemia and was found to have new onset Graves' disease.