Treatment with vandetanib in a 11 years old boy with advanced medullary thyroid carcinoma

PAPENDIECK, P.; ELIAS, E; GARCIA LOMBARDI, M; BERGADÁ, I; CHIESA, A

Washington

Congreso; 10th International Meeting of Pediatric Endocrinology; 2017

An 11 year old boy had a longstanding history of hypotonia and gastrointestinal symptoms. Electromyography suggested a motor polyneuropathy. Gastrointestinal symptoms started at 3 months of age with diarrhea alternating with constipation. Since the age of 8 years he presented loose stools and incontinence, requiring diapers and home education. No definitive diagnosis was made. Before admission to our hospital a spinal and CNS MRI revealed a heterogeneous multinodular goiter (MNG) with multiple cervical and mediastinal adenomegalies. Physical exam showed a lean boy (BMI:12.5), with normal stature and marfanoid phenotype, thick eyelids and lips and multiple small whitish nodules on his tongue. Cervical examination revealed a MNG with cervical adenomegalies. TSH was 8.25 mU/I with normal thyroid hormones, negative thyroid antibodies, circulating calcitonin 58085 pg/ml(RV:0 - 46) and normal catecolamines. Cervical ultrasound showed left dominant heterogeneous nodule with increased central vascularization and microcalcifications, and 2 small right nodules with microcalcifications with multiple abnormal lymphadenopathies. FNAB was positive for medullary carcinoma (MTC) with positive wash out for calcitonin. Bone scan was negative but multiple pulmonary metastases were found on CT. Protooncogen RET mutation c.2753T>C.p.M918T was found in exon 16 confirming MEN 2B syndrome. He underwent partial thyroidectomy with left neck dissection. In the presence of a locally and distant metastatic MTC treatment with vandetanib (100 mg/day) was started. After the first month calcitonin decreased by 90%. Currently after 7 month of treatment his serum calcitonin is 9000 pg/ml. Gastrointestinal symptoms dramatically improved and allowed school reinsertion. Photosensitivity was the only adverse event and was managed with local treatment. Although with a short time of treatment, vandetanib has stabilized his illness and allowed a better quality of life.