Marine-Lenhart syndrome

Marine-Lenhart syndrome refers to a variant of Graves disease where there are coexistent autonomous thyroid nodules. It is better described as Graves disease with coexistent multinodular goiter or nodular Graves disease .

Epidemiology

The syndrome is rare with reported prevalence somewhere between 1-4.1% in patients with Graves disease .

Pathology

Occurrence of Graves disease, with stimulatory autoantibodies to thyroid-stimulating hormone (TSH) receptor, with coexisting nodularity of the thyroid gland.

Radiographic features

Ultrasound

Depicts both nodules and thyroiditis. Features suggesting thyroiditis are:

  • diffusely enlarged gland
  • diffusely hypoechoic parenchyma
  • markedly increased vascularity, so-called "thyroid inferno"

The ultrasound appearances are usually indistinguishable from Hashimoto or de Quervain thyroiditis, however, the clinical picture and blood samples usually make diagnosis straightforward.

Nuclear medicine

Can be done with Tc-99m pertechnetate or I-123 iodine.

Imaging appearances are those of a generally high degree of uptake (as in Graves disease) together with one or more nodules lacking significant uptake i.e. cold nodules.

In the course of therapy, along with normalization of TSH levels, these initially cold nodules may alternate their degree of uptake, not infrequently changing to hot nodules .

Treatment and prognosis

Initial therapy usually consists of antithyroid drugs. Once thyroid hormone levels are under control, definite therapy options comprise:

  • radionuclide therapy (once malignancy is ruled out) and
  • surgery (which some authors prefer for multiple nodules). 

History and etymology

It was first described in 1911 by the American surgeons David Marine and Carl H Lenhart in Cleveland, Ohio, on histopathological and iodine content studies of goiter. They encountered eight cases of synchronous goiter and adenoma .

Differential diagnosis

A list of differential diagnoses for cold nodules comprise both benign and malignant entities, which have been quantified in one larger single-center study :

  • great majority comprising benign entities such as:
    • autoimmune changes
    • coexisting nodular goiter
  • incidence of thyroid malignancy in ~10% of all nodules

Scintigraphically-cold nodules with sonographic features suspicious for malignancy are usually biopsied, especially before radioiodine therapy.

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