ESPE Abstracts

Thyroid cancer in children is not common but there is a tendency to increase requiring early suspicion and close monitoring of thyroid nodule. Papillary thyroid cancer (PTC) is the most common type of thyroid cancer and medullary thyroid cancer (MTC) is rare, MTC can be suspected if there is elevated calcitonin level. A 15-year-6-month-old girl was admitted for generalized tonic seizure with fever. Initial Brain MRI showed a small oval diffusion restriction lesion in the midline of corpus callosum splenium. EEG did not reveal any epileptiform discharges. Urinary tract infection with acute pyelonephritis was proven with urine analysis, kidney ultrasound, and kidney scan. Initial blood test showed severe hypophosphatemia 0.9 mg/dl (2.7-4.5). Tubular reabsorption of phosphorus was 96%and parathyroid hormone (PTH), Vitamin D, and calcitonin levels were 72.7 pg/ml (10-57), 10.7 ng/ml (30-100), and 9744 pg/ml (0-10), respectively. After normalization of phosphorus to 3.7 mg/dl, calcitonin was decreased to 942 pg/ml, but it was still very high suggesting malignancy. Under the impression of MTC, thyroid ultrasonography was performed which revealed a lobulated taller-than-wide, 0.6×0.7×0.6 cm sized nodule, suggesting highly suspicious malignancy (K-TIRADS category 5). Her mother had also thyroid nodule, proven papillary thyroid cancer and right lobectomy was done. RET gene mutation was checked but no pathogenic variant was detected. 24 hour-urine VMA, catecholamine, metanephrine, and normetanephrines levels were within normal ranges. Fine needle aspiration was done and it showed atypia of undetermined significance. The patient was then consulted to general surgeon for thyroidectomy and the pathology turned out to be PTC in right lobe, with lymph node invasion (8 LN of 22 LNs). The TNM staging of cancer was T1N1MO. Post-operative parathyroid hormone and calcitonin levels became normalized (PTH 5.6 pg/ml, calcitonin 6.9 pg/ml). This case showed that PTC can not be ruled out although there is highly elevated calcitonin level. Here we report a case of incidentally detected papillary thyroid cancer with elevated calcitonin in a 15 year-old female.