Endocrine Abstracts

Introduction: Neuroendocrine lesions in the thyroid gland are uncommon. The differential diagnosis usually includes medullary thyroid carcinoma, paraganglioma and metastases. There are few non-conclusive reports of primary neuroendocrine carcinomas of the thyroid.

Clinical case: A 49-year-old woman with a past medical history for familial hypercholesterolemia and right oophorectomy for mature teratoma with struma ovarii, was evaluated for a rapidly growing cervical mass. A firm, hard, enlarged right thyroid lobe was detected on physical examination. Neck ultrasound, full-body-computerized-tomography (CT) and PET-CT were performed. The latter showed a 49×32×59 mm mass with high metabolic activity in the right thyroid lobe infiltrating the trachea, esophagus and sternohyoid and platisma colli muscles as well as ipsilateral cervical adenopathies and an unspecific milimetric nodule in the upper left pulmonary lobe. Full blood count and biochemistry were normal apart from a total cholesterol of 461 mg/dl; she was euthyroid with negative thyroid autoimmunity; undetectable calcitonin, normal catecholamines, 5-HIIA, β2-microglobulin and CEA. Neuron specific enolase was slightly increased (17.32 ng/ml, normal 0–16 ng/ml). Cervical lymph node biopsy consistent with metastases from large cell neuroendocrine carcinoma (LCNC). Total thyroidectomy, total laryngectomy and right cervical lymphadenectomy were performed, revealing a LCNC invading blood vessels, soft tissue and laryngeal adventitia; negative immunostaining for calcitonin and tiroglobulin, positive for TTF-1 and CD56; Ki-67 >90%. Postsurgical ¹¹¹In-pentetreotide scintigraphy was negative. She received six cycles of cisplatin-etoposide. One year after diagnosis there is no biochemical or radiological evidence of persistent disease.

Conclusions: We cannot fully exclude the possibility of a metastatic primary lung tumor, but the clinical course, the size of the thyroid mass, the absence of any other clear lesion outside the neck and the immnunostaining pattern suggest a primary thyroid LCNC. To the best of our knowledge, this could be the first case report of these tumors arising in this location.

Declaration of interest: The authors declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research project.

Funding: This research did not receive any specific grant from any funding agency in the public, commercial or not-for-profit sector.