Primary thyroid paraganglioma presenting with double thyroid nodule: a case report.

Paragangliomas (PGs) are exceptionally rare tumors. Only 24 cases have previously been reported. Both preoperative and postoperative differential diagnosis is very difficult. Due to interesting nature in diagnosis and differential diagnosis, we describe the case 58-year-old euthyroid woman with a thyroid PG. The patient had presented with euthyroid multinodular goiter to a secondary hospital. The patient was treated with right lobectomy, isthmectomy, and left partial lobectomy without any imaging procedures. No complication had been developed during and following the operation. Initial pathological examination suggested medullar thyroid carcinoma (MTC) in a nodule of 4.5 cm in diameter on right thyroid lobe and a nodule of 2.5 cm in diameter on the left thyroid lobe without amyloid stroma and referred to our third-stage hospital. Repeated pathological examination involving immunohistochemistry revealed that the tumor was stained positively to neuron-specific enolase, chromogranin A, synaptophysin, and S-100 protein. No immunoreactivity was detected against thyroglobulin, calcitonin, parathormone, carcino-embryonic antigen, thyroid transcription factor-1, and cytokeratin. A diagnosis of thyroid PG was finally made. Laboratory analyses and imaging procedures excluded any neck or extracervical tissues metastasis or multiple endocrine neoplasia. In conclusion, thyroid PG is an elusive tumor. We present this interesting nature thyroid PG case to highlight importance of careful evaluation of clinical and pathological findings to correctly identify paragangliomas which anatomically mimic MTCs. This report is the first case of thyroid PG presenting with multinodular goiter in the literature.