Endocrine Abstracts

Introduction: Thyroid hyperfunctioning nodule usually represents benign tumor. Less than 1% of all cases have been reported as malignant lesion, especially in the presence of hyperthyroidism.

Case report: An asymptomatic 46-year-old man with a history of diabetes mellitus type 2 came for regular diabetic check. Two palpable thyroid nodules were detected during a routine physical examination. Thyroid function tests showed hyperthyroidism: TSH <0.005 mIU/L (0.63–4.19), FT4 31.1 pmol/L (11.5–22.7), FT3 9.7 pmol/L (3.5–6.5). Antithyroglobulin and antiperoxidase antibodies were present in elevated titre. Thyroid scintigraphy (Tc-99m pertechnetate) revealed mildly decreased glandular activity, a hyperfunctioning nodule in the left lobe and a nonfunctioning nodule in the right lobe. Thyroid ultrasound showed hypoechoic nodule (volume 3.3 ml) containing microcalcifications in the left lobe and hypoechoic nodule (volume 1.5 ml) in the right lobe. US-guided fine-needle aspiration cytology (FNAC) of a nonfunctioning nodule showed clusters of thyrocytes, phagocytes, and diffuse colloid. FNAC of the hyperfunctioning nodule was also done due to suspicious ultrasound nodule features, enlarged ipsilateral lymph nodes highly suggestive for malignancy and it revealed features of papillary carcinoma. Treatment with thiamazole was started and patient was subjected to operation as soon as he became euthyroid. A total thyroidectomy and level III, IV and V selective neck dissection were performed. Histology confirmed follicular variant of papillary carcinoma with intraglandular tumor dissemination and regional lymph nodes metastases. Postoperative whole body scintigraphy with 131I showed large inhomogeneous RI activity in the projection of the anterior cervical region. The patient received 100 mCi of the 131I for thyroid remnant ablation and levothyroxine treatment was started.

Conclusions: Papillary thyroid carcinoma rarely exists in an autonomously hyperfunctioning nodule. Clinicians should be aware that hyperfunctioning nodule, even if hyperthyroidism is present, does not exclude the presence of a well differentiated thyroid carcinoma. Although this pathology is rare, it is important to be correctly diagnosed and appropriately treated.

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