Synchronous Presentation of Type 2 Marine–Lenhart Syndrome and Differentiated Thyroid Carcinoma Manifesting as Thyroid Storm

Marine-Lenhart syndrome (MLS) is a rare condition characterized by the coexistence of hyperfunctioning thyroid nodules and Graves' disease (GD). The prevalence of thyroid nodules and thyroid cancer is higher in patients with GD. We report a case of 42-year-old female who presented with thyroid storm and found to have underlying GD. An initial thyroid ultrasound (US) revealed two nodules classified as TIRADS 3, whereas a repeat US after achieving euthyroidism, showed changes in the size and consistency of these nodules and identified a new nodule with classification of TIRADS 6 nodule. A 24-h radioactive iodine thyroid uptake scan demonstrated a diffuse increase uptake (75.1%) with one hyperfunctioning and two warm nodules, including the newly identified TIRADS 6 nodule. Fine-needle aspiration (FNA) biopsy confirmed papillary thyroid cancer (Bethesda VI) in a right (R) warm nodule (the TIRADS 6 nodule), while the other two nodules were benign (Bethesda II). The patient underwent a R hemithyroidectomy that was complicated by recurrent laryngeal nerve (RLN) injury. Pathology examination revealed unifocal papillary thyroid microcarcinoma with positive anterior surgical margin. The patient was furtherly treated with radioactive iodine therapy thyroid nodules with GD should be managed cautiously. Emerging evidence challenges the previous notion that hyperthyroidism provides protection against thyroid cancer. The association between GD and thyroid malignancy remains an area of ongoing investigation, with variable management strategies and prognostic implications reported in the literature.