A Case of Marine-Lenhart Syndrome with a Negative TSH Receptor Antibody Titer Successfully Treated with a Fixed, Low Dose of I¹³¹

Abstract

We herein describe a case of Marine-Lenhart syndrome with a negative TSH receptor antibody titer. A 75-year-old female presented to our hospital with malaise, palpitations, and mild fine tremors. She did not have any signs suggestive of Graves' ophthalmopathy, including conjunctival injection, periorbital edema, or proptosis. Her laboratory data were negative for thyroid autoantibodies, including anti-thyroid peroxidase antibodies, anti-thyroglobulin antibodies, and anti-TSH receptor antibodies (TRAb). Ultrasonography of the thyroid gland revealed a tumor in the right lobe. The remaining thyroid gland had an inhomogeneous and rough texture with a high color Doppler flow. I123 scintigraphy disclosed a hot nodule in the right thyroid gland corresponding to the tumor detected on ultrasonography, suggesting Plummer disease. Furthermore, there was an increased uptake of radionuclide in the rest of the thyroid gland, despite the suppressed level of TSH and negative titer of TRAb, suggesting underlying Graves' disease. The present findings suggested a diagnosis of Marine-Lenhart syndrome with a negative TRAb titer. Treatment with 10 mCi of radioiodine was highly effective in treating hyperthyroidism in this case. A negative TSH receptor antibody titer does not necessarily rule out the existence of Graves' disease in patients with Plummer disease.

Síndrome de Marine Lenhart: reportes de caso de una presentación inusual de hipertiroidismo

“…Dichos autoanticuerpos, actúan también sobre otras células donde se encuentre su receptor, principalmente sobre adipocitos y fibroblastos del tejido graso periorbitario, pudiendo causar orbitopatía debido al aumento del tejido muscular, conectivo y adiposo periorbitario por la proliferación de los fibroblastos e inflamación inducida por estos anticuerpos (9). Se han asociado los autoanticuerpos de la enfermedad de Graves al desarrollo de los nódulos tiroideos autónomamente funcionantes (10), propios del síndrome de Marine Lenhart, sin embargo, en la literatura se encuentran 3 reportes de caso que describen la presencia del síndrome de Marine Lenhart con títulos (TRAb) negativos y hallazgos radiológicos compatibles con la patología (11)(12)(13).…”

Prevalence and Treatment Outcomes of Marine-Lenhart Syndrome in Japan

“…Thereafter, the coexistence of thyroid functioning nodule(s) and Graves' disease has been called MLS. Thus, the definition and concept of this syndrome have changed with time: "TSH-dependent functional nodule(s)" [8,24,25] and "coexistence of Graves' disease and AFTN" [2,6,7,9,10,[12][13][14][15][16][17][18][19][26][27][28][29]. However, most of the previous reports emanated from studies conducted in iodine-defi-cient areas.…”

Marine-Lenhart Syndrome: Case Report, Diagnosis, and Management

“…A PubMed search using the term “Marine-Lenhart” at the time of writing this report returned 33 articles and the most relevant are reported in Table 1. Both “cool,” although it is unclear if hyper-functioning, and “hot” nodules are described in patients with Graves' disease [9, 10, 12, 13, 15–21]. Cases of Marine-Lenhart with papillary thyroid carcinomas are also described [6–8, 14].…”