Background: Graves disease (GD) typically manifests as an autoimmune hyperfunction of both thyroid lobes. Less than 10 cases of unilateral GD have been described, and the pathophysiology of unilateral GD remains unknown. Co-existence of malignancy has never been reported. We report a case of GD of the left lobe with simultaneous discovery of a papillary carcinoma within the hyperfunctioning lobe.
Case description: A 49-year-old patient of Middle-Eastern origin was referred to our clinic in November 2016, one year after the diagnosis of symptomatic thyreotoxicosis, treated by carbimazole for the first 6 months. Subclinical hyperthyroidism recurred after treatment withdrawal. Thyroid isotope scanning with 99Tc in September 2016 showed diffusely increased uptake of the left lobe (with the exception of a low uptake zone) and minimal uptake of the right lobe. In November 2016, the patient was asymptomatic and had subclinical hyperthyroidism. Thyroid gland ultrasonography (US) showed a slightly enlarged and heterogeneous left lobe with clearly increased vascularity. The right lobe was smaller, homogeneous, with normal vascularity confined to its periphery. Based on the imaging results and positive thyrotropin receptor antibodies, unilateral GD was diagnosed. The low uptake zone in the left lobe corresponded to a hypoechoic nodule with suspicious US features (central calcification, possible infiltration of the thyroid capsule). Fine-needle biopsy of this lesion revealed papillary carcinoma (Bethesda class VI). Total thyroidectomy will soon be performed.
Conclusion and perspectives: GD can rarely present with an asymmetric involvement of the thyroid lobes. Our patient is the first case associating unilateral GD and thyroid malignancy in the ipsilateral lobe. Given that total thyroidectomy is indicated, complete histological, biochemical and genetic evaluation of both lobes will allow us to test current hypotheses on the pathophysiology of unilateral GD.
20 - 23 May 2017
European Society of Endocrinology