Thyroid Paraganglioma- An Unusual Head and Neck Tumour

Paragangliomas are neuroendocrine tumour originating from the neural crest-derived paraganglia with majority arising from the head and neck. (1)Thyroid paraganglioma are exceedingly rare neuroendocrine tumours accounting for <0.1% of thyroid malignancy (1) We present a 57 years old gentleman who was referred to ENT surgeon following discovery of a two month history of lump on his left neckIt has not changed in size and not caused any symptoms such as anxiety, sweats, palpitations, dizziness or unexplained headaches. He has a Past medical history of epilepsy following a Road traffic accident 28 years ago leaving him seizure prone. He has no family history of neuroendocrine tumours His ultrasound scan of his thyroid gland showed a 25 x 23 x 15mm lesion lying anteriorly within the left thyroid lobe. There are two highly reflective foci which could represent microcalcification. It was classified as U5 lesion He proceeded with fine needle aspiration which confirmed carcinoma of the left thyroid gland with no clear differentiation between follicular or papillary carcinoma. He undergone a total thyroidectomy and left central level VI lymph node dissection His histology confirmed a thyroid paraganglioma staining strongly positive for neuroendocrine markers (Synaptophysin and chromogranin) while S-100 shows positivity in the sustentacular cells. He was referred for genetic testing which demonstrate no evidence of mutation in FH, SDHAF2, SDHB/C/D, RET, MAX, TMEM127 and VHL gene. He was commenced on levothyroxine replacement at a dose of 150micrograms OD. His urine metanephrines is 178.1pmol/L (0-510), urine normetanephrines 192.9pmol/L (0-1180) and 3-methoxytyramine <75pmol/ L (0-180) (all normal). His MRI neck revealed no synchronous tumour. He continues to be followed up under our endocrine clinic. Conclusion: Due to the rarity of these tumours, their natural history is mostly unknown. Nevertheless, postoperative surveillance should include plasma or urinary metanephrines and ultrasonography. References: 1 https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3824793/