Endocrine Abstracts

Introduction: Paragangliomas are rare neuroendocrine neoplasms arising from chromaffin cells in the sympathetic or parasympathetic neural paraganglia that may appear in many places throughout the body. These might be benign or malignant tumors. We report an interesting case of disseminated paraganglioma, the diagnosis of which began with the metastasis to the thyroid gland.

Case presentation: A 69-year-old patient with a history of toxic multinodular goiter, treated with antithyroid drugs for approximately two years. Cytological features of papillary thyroid cancer were found in a fine needle aspiration biopsy. The patient underwent total thyroidectomy with central neck dissection. Primary histopathological diagnosis was a multifocal thyroid paraganglioma. Post-operative evaluation revealed solid liver lesion on abdominal ultrasound. Cell-block of liver biopsy indicated well-differentiated neuroendocrine tumor cells. Laboratory tests showed Increased levels of chromogranin A, calcitonin, CEA, CA19-9, AFP, HE4. Moreover, we observed elevated concentrations of 3-metoksythyramine in 24-hour urine collection, with normal concentrations of metanephrines and normetanephrines. Ga-68 DOTATATE PET/CT revealed lesions with an increased expression of somatostatin receptors: intervertebral foramen infiltration at level C7/Th1, metastases to the brain, bones, liver, thyroid and adrenal gland. Next Generation Sequencing of blood did not detect pathogenic mutations SDHA, SDHB, SDHC, SDHD, VHL, RET, MAX, SDHAF1, SDHAF2. The patient was treated with palliative radiotherapy to the spine.

Conclusions: Diagnosing paraganglioma with fine needle aspiration biopsy in the thyroid gland might be difficult. It can be misdiagnosed as other thyroid tumors, like papillary neoplasms, follicular neoplasms or medullary thyroid cancer. Histopathological diagnosis of thyroid paraganglioma requires differentiation between an extremely rare primary thyroid paraganglioma and metastatic neuroendocrine tumor. Good cooperation between the clinician and pathomorphologist is crucial for the appropriate diagnosing and subsequent treatment.