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

Abstract

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.

A case of Marine Lenhart syndrome with Hashimoto’s thyroiditis that mimicked thyroid carcinoma

“…In the case we presented, production of hot nodules may be mostly related to the stimulation of TRAb, as discussed elsewhere [ 9 , 10 ]. Due to coexistence of Hashimoto's thyroiditis, it may also be related to the various degrees of follicular degeneration and hyperplasia.…”

Marine-Lenhart syndrome with a cold nodule: an uncommon entity

“…Marine-Lenhart syndrome is defined as the coexistence of Graves’ disease and AFTN 1. The syndrome is quite rare, estimated to occur in around 0.8%–2.7% of patients with Graves’ disease 2…”

“…The patient was informed in detail about all possible treatment options (radioiodine therapy, antithyroid drugs and surgery). Radioiodine therapy has the advantage of permanent resolution of the disease; however, a greater dose is necessary in Marine-Lenhart syndrome (MLS) 1. Surgery also provides a permanent cure, however, there are risks of permanent hypothyroidism, iatrogenic hypoparathyroidism and recurrent laryngeal nerve damage.…”