Difficulties in the diagnosis of thyroid paraganglioma: a clinical case.

Thyroid Paragangliomas are exceptionally rare tumors and only 35 documented cases have been reported in the literature. We report an additional unusual male case of thyroid Paraganglioma associated to a chronic lymphocytic thyroiditis and a papillary microcarcinoma. A 45-year-old man presented with a solitary thyroid nodule. Physical examination revealed a smooth, well-circumscribed, firm, mobile, painless thyroid nodule in the right lobe measuring 3 cm. Ultrasound examination showed a 40 mm hypoechoic, non-homogeneous nodule with peri- and intra-nodular vascular flow. An ultrasound-guided fine needle aspiration biopsy was performed showing the presence of atypical cells (Thy 3). He underwent a total thyroidectomy associated to VI level lymphectomy. Histology showed a thyroid Paraganglioma associated to a chronic lymphocytic thyroiditis and a papillary microcarcinoma measuring 0.3 cm in the greatest dimension. Thyroid Paraganglioma is an elusive tumor. It is difficult to diagnose and should be included in the differential diagnosis of all neuroendocrine tumors of the thyroid, even those arising in men or behaving in a locally aggressive fashion.