Journal of Clinical and Diagnostic Research, ISSN - 0973 - 709X

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Case report
Table of Contents - Year : 2016 | Month : June | Volume : 10 | Issue : 6 | Page : PD10 - PD12

Diagnostic Dilemma in a Thyroid Incidentaloma: Second Primary versus Metastatic Nodule? PD10-PD12

Abid Ali Mirza, Esha Pai, Kodaganur Gopinath Srinivas, Shankarappa Amarendra, K.S Gopinath

Dr. Esha Pai,
802, Olive 1, Prestige St. Johns Woods, 80 St. Johns Cross Road, Koramangala, Bangalore -560029, India.

With the increasing use of 18F-Fluro-Deoxyglucose (FDG) Positron Emission Tomography (PET) the number of thyroid incidentalomas is on the rise. Focal thyroid incidentalomas identified by FDG-PET have been reported to have a high incidence of malignancy. Neuroendocrine tumours of the thyroid are rare entities. The most common neuroendocrine tumour of the thyroid is medullary carcinoma. A thyroid nodule in a patient with a known neuroendocrine tumour must be differentiated from a primary medullary carcinoma which can present a diagnostic challenge to the clinician. A 65-year-old female patient was referred for thyroidectomy for a FNAC diagnosed follicular neoplasm of the left lobe of the thyroid, detected on FDG PET follow up. She was a known case of neuroendocrine tumour of the pancreas with no features suggestive of familial Multiple Endocrine Neoplasia (MEN) syndrome. The patient had undergone Whipple’s procedure elsewhere, 5 years back. Following total thyroidectomy, the final histopathology report was suggestive of a primary neuroendocrine tumour. We present this case to highlight the clinical dilemma in diagnosing a thyroid incidentaloma as a second primary neuroendocrine tumour versus a solitary metastatic nodule in the background of metastatic gastroentero pancreatic neuroendocrine tumour. Although clinically, a metastatic nodule should have been the obvious diagnosis, the histopathological and immunohistochemical features were in favour of a primary non-medullary Neuroendocrine Tumor (NET) of the thyroid.