Case report: prophylactic thyroidectomy for increasing calcitonin levels?
Katie Wynne, Anthony Goldstone, Fausto Palazzo, Jeannie Todd & Karim Meeran
A 19-year-old man was referred to Endocrinology Clinic with a minimally raised calcitonin level. He had a past history of primary hyperparathyroidism resulting in renal colic aged 17 years, and underwent three gland parathyroidectomy aged 18 years. Histology demonstrated a single right lower parathyroid adenoma with normal thyroid biopsy. He has no family history of endocrine disease and is a non-smoker. His calcium has remained normal since with detectable PTH. Over 5 years there has been a progressive increase in his basal calcitonin level:
|Date||Feb 04||Sep 05||JulOct 06||Dec 06||Feb 07||Jul 08|
|Peak calcitonin during a pentagastrin stimulation test was *152.0 in 2004 and **173.0 in July 2008.|
His CEA, urinary catecholamines and fasting gut hormones have remained normal. Genetic screening for MEN-1 and MEN-2 (RET exons 120) was negative. Yearly thyroid ultrasound scans have been normal. An MRI neck scan was normal in 2004, and a Dimercaptosuccinic Acid (DMSA) scan was normal in 2006. He is now 24 years old. Despite the development of primary hyperparathyroidism at a young age and an increasingly elevated calcitonin level, there has been no histological evidence of C-cell hyperplasia, genetic evidence for increased risk of medullary thyroid carcinoma (MTC), nor radiological evidence of MTC. There are surgical risks of hypoparathyroidism and voice change with repeat neck surgery. Our Multidisciplinary Endocrine Meeting has concluded that there is no current indication for prophylactic thyroidectomy. The follow-up plan is for annual assay of calcitonin and neck ultrasound scans with fine needle aspiration of any thyroid nodules. In the absence of a suspicious nodule, it is open for discussion whether there is a level of basal or stimulated calcitonin which should prompt further consideration of prophylactic thyroidectomy.