Endocrine Abstracts

Background: The combination of a toxic adenoma and Graves’ disease compose the Marine-Lenhart syndrome. It is estimated to occur in 0.8–2.7% of Graves’ disease and only few are reported.

Case presentation: A 29-year old female was referred to our clinic due to subclinical hyperthyroidism and a newly discovered thyroid nodule on the right thyroid lobe. She had no thyreotoxic symptoms and the clinical examination was unremarkable. The blood tests showed: TSH 0.01 mU/l (reference 0.16–4.25 mU/l), fT3 8.3 pmol/l, (reference 3.6–6.4 pmol/l), fT4 15.6 pmol/l (reference 12.3–20.2 pmol/l) and TSH-Receptor-Ab titers < 0.30 U/l (reference < 1.75 U/l). The thyroid ultrasound and scintigraphy revealed a toxic adenoma in a right sided goiter. Following a radioiodine ablation with 200 MBq 131-I was performed. Follow-up ultrasound after six months revealed a 70%-volume reduction of the formerly toxic adenoma of (2.6 ml, pre-therapy 8.7 ml). Two months later at the regular after-therapy follow-up, a manifest hyperthyroidism was revealed [TSH 0.004 mU/l, fT3 28.1 pmol/l and fT4 21.4 pmol/l] and the TSH-Receptor-Ab titers were elevated [1.85 U/l], while the patient was asymptomatic. A new thyroid scintigraphy showed a symmetrical, elevated uptake, leading to the diagnosis of Graves’ disease. A thyrostatic therapy with carbimazole was initiated for 8 months, until the thyroid function markers were normalised.

Conclusions: The co-existence of both a toxic adenoma and a Graves’ disease is termed Marine-Lenhart syndrome. It may be observed simultaneously or in different stages, according to the bibliography. In cases where radioiodine treatment of a toxic adenoma is indicated, attention is required, because it may trigger the Graves’ disease, as shown in this case. Every new presentation of hyperthyroidism should be investigated as a new pathology, as it may reveal a new underlying condition indicating the need for different therapeutical pathways.