The Marine-Lenhart syndrome revisited

Type 2 Marine-Lenhart Syndrome: An Uncommon Cause of Thyrotoxicosis

Marine-Lenhart syndrome (MLS) is an uncommon cause of primary hyperthyroidism, which can occur in the context of diffuse goiter due to Graves disease (GD) or autonomic nodular disease (Plummer disease (PD)). The coexistence of these two conditions is the hallmark of the MLS. Patients with MLS have a lower remission rate with oral antithyroid drugs, requiring definitive management therapies with radioactive iodine or surgery. We present the case of a 48-year-old female with a history of primary autoimmune hyperthyroidism (GD) since 2016, with biochemical control of hyperthyroidism with methimazole but without the possibility of stopping treatment. The scintigraphic uptake pattern showed heterogeneous uptake of the thyroid parenchyma with three hyper-uptake nodules without inhibition of the rest of the thyroid tissue, findings of an MLS condition with the indication for definitive therapy, for which he was referred to nuclear medicine for the administration of radioactive iodine.

Prevalence and Treatment Outcomes of Marine-Lenhart Syndrome in Japan

INTRODUCTION

Marine-Lenhart syndrome (MLS) is now understood to be a combination of Graves' disease and autonomously functioning thyroid nodule(s) (AFTNs). The prevalence of the syndrome and suitable treatments for those living in iodine-sufficient areas are uncertain.

OBJECTIVES

We aimed to investigate the prevalence, treatment, and prognosis of MLS in Japan, an iodine-sufficient area.

METHODS

This study involved patients who visited our hospital between February 2005 and August 2019. Among patients with both thyrotoxicosis and thyroid nodule(s) larger than 10 mm, MLS and isolated AFTNs were diagnosed based on serum thyroid-stimulating hormone receptor antibody levels and scintigraphy using radioiodine or technetium-99m and thyroid uptake.

RESULTS

Twenty-two patients were found to have MLS, compared to 372 with isolated AFTNs and 8,343 with Graves' disease, during the period. Therefore, the rate of MLS cases was 0.26% among all patients with Graves' disease (22/8,343). Treatments and outcomes were assessed for cases of MLS (n = 18) and isolated AFTNs (n = 269). Antithyroid drugs (ATDs) were withdrawn in 27.8% of cases in the MLS group and 10.3% in the isolated AFTN group. There was no significant difference in the clinical outcome after ATD withdrawal between the 2 groups. However, the rate of hypothyroidism after radioactive iodine (RAI) administration was significantly higher in the MLS group than in the isolated AFTN group (42.9 vs. 9.0%, p = 0.005) despite similar doses of RAI.

CONCLUSIONS

The prevalence of MLS among patients with Graves' disease was 0.26% in Japan. RAI therapy induces hypothyroidism more frequently than in those with AFTNs probably because RAI is taken up in the surrounding Graves' tissues.

A marked goiter involved in Marine-Lenhart syndrome

Marine-Lenhart syndrome is rare disease defined as coexistence of Graves' disease and autonomously functioning thyroid nodule. We will introduce a case of Marine-Lenhart with a huge goiter.

A new case of Marine-Lenhart syndrome with a papillary thyroid carcinoma

We report the case of a patient with the coexistence of Graves' disease and autonomously functioning thyroid nodules. Because of the suspicious ultrasound pattern, he was submitted to fine-needle aspiration of the hot nodule and cytology revealed a papillary thyroid cancer. After total thyroidectomy a papillary thyroid cancer was found.

An uncommon case of Marine-Lenhart syndrome

The term Marine-Lenhart syndrome describes the association between Graves' disease and autonomously functioning thyroid nodules (AFTN), such as toxic adenoma or toxic multinodular goiter. The two diseases may coexist or may be present at different moments in the same patient. In the literature, there are many reports on the development of Graves' disease after radioiodine treatment for AFTN, but very little information may be found on the occurrence of AFTN after radioiodine therapy for Graves' disease. We describe here the case of a female patient with Graves' disease who was successfully treated with radioiodine for Graves' disease, returning to normal thyroid function. Three years later, biochemical analysis and ultrasound examination identified a thyroid nodule that progressively increased in size. The 99mTc-pertechnetate scintigraphy showed avid uptake in the right lobule, which corresponded to a nodular lesion consistent with AFTN.

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

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.

A Case of simultaneous occurrence of Marine - Lenhart syndrome and a papillary thyroid microcarcinoma

BACKGROUND

Marine-Lenhart syndrome is defined as the co-occurrence of Graves' disease and functional nodules. The vast majority of autonomous adenomas are benign, whereas functional thyroid carcinomas are considered to be rare. Here, we describe a case of simultaneous occurrence of Marine-Lenhart syndrome and a papillary microcarcinoma embedded in a functional nodule.

CASE PRESENTATION

A 55 year-old, caucasian man presented with overt hyperthyroidism (thyrotropin (TSH) <0.01 μIU/L; free thyroxine (FT4) 3.03 ng/dL), negative thyroid peroxidase and thyroglobulin autoantibodies, but elevated thyroid stimulating hormone receptor antibodies (TSH-RAb 2.6 IU/L). Ultrasound showed a highly vascularized hypoechoic nodule (1.1 × 0.9 × 2 cm) in the right lobe, which projected onto a hot area detected in the 99mtechnetium thyroid nuclear scan. Overall uptake was increased (4.29%), while the left lobe showed lower tracer uptake with no visible background-activity, supporting the notion that both Graves' disease and a toxic adenoma were present. After normal thyroid function was reinstalled with methimazole, the patient underwent thyroidectomy. Histological work up revealed a unifocal papillary microcarcinoma (9 mm, pT1a, R0), positively tested for the BRAF V600E mutation, embedded into the hyperfunctional nodular goiter.

CONCLUSIONS

Neither the finding of an autonomously functioning thyroid nodule nor the presence of Graves' disease rule out papillary thyroid carcinoma.

[Radiologic and nuclear medicine diagnosis and therapy of thyroid disorders. Part 1: Benign thyroid diseases]

The thyroid gland is one of the most important endocrine organs. It has multiple influences on physical and mental health. The most important benign diseases are goiter, thyroid adenomas and inflammation. The clinical, imaging and laboratory findings are often pathognomic. The therapy spectrum ranges from follow-up, to medication or definitive therapy by operation or radioiodine therapy.