RESUMO
Thyroid isthmus agenesia (TIA) which is characterized by the absence of isthmus is one of these anomalies and its etiology is unclear. Marine Lenhart Syndrome (MLS), on the other hand, is defined as the coexistence of Graves disease and hyperactive nodules,although the diagnostic criteria are not clearly defined. Fifty five years old male patient with no concomitant disease had been diagnosed with MLS and accompanying subclinical hyperthyroidy for two years. He had dysphagia for a year. Neck ultrasound revealead retrosternal goiter with multiple hypoechoic nodules with the largest size of 33x30 mm. He had normal FT3 and FT4 levels with a decreased level of TSH. Scintigraphy revealed diffuse thyroid uptake with a hyperactive nodule of 16x11 mm on right upper lobe. Due to compressive sypmtoms and MLS he underwent surgery and diagnosed with thyroid isthmus agenesia peroperatively. MLS and TIA are rare thyroid pathologies and their etiopathogenesis has not been clarified yet. This case is thought to be the first case in which MLS and TIA coexistence was reported. Even though it is a rare disorder,having a basic knowledge about TIA can be an important step in establishing a treatment plan and avoiding possible complications. Especially in management of MLS, when surgery is considered the physician should be careful for presence of a TIA.
