Marine-Lenhart syndrome in two adolescents, including one with thyroid cancer: a case series and review of the literature

Abstract

Background: The coexistence of functional thyroid nodules and Graves' disease (GD) is a rare condition known as Marine-Lenhart syndrome. Thyroid cancer has been described in several adults, but never in children, with Marine-Lenhart syndrome. This paper discusses the challenges in diagnosis and the unique management of this condition in children, in the context of extant literature. Content: In this case report, two adolescent female patients with Marine-Lenhart syndrome, aged 15 and 16 years, exhibited biochemical evidence of hyperthyroidism, and were found to have unilateral hyperfunctioning thyroid nodules via thyroid scintigraphy. Additionally, both patients showed elevated thyroid-stimulating immunoglobulins (TSI) and increased glandular activity, confirming background GD. Notably, one patient was also diagnosed with intranodular thyroid cancer upon preoperative examination. Both patients were treated via surgical resection. Summary and outlook: Diagnosis of Marine-Lenhart syndrome can be made in patients with functional thyroid nodules and increased glandular activity on thyroid scintigraphy. Standard doses of radioiodine ablation are not effective in the majority of patients and should be avoided due to the increased risk for thyroid cancer, making thyroidectomy the preferred treatment.

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

“…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]. In order to reconcile the above discrepancies in the definition of the Marine-Lenhart syndrome, we propose the following criteria for the diagnosis and classification of patients with Graves' disease and functioning nodules: (1) thyroid function tests consistent with hyperthyroidism inclusive of serological testing for Graves' disease (TRAb/TSI); (2) increased radioiodine uptake and the presence of “cool” or “hot” nodules; thyroid nodularity should be supported by ultrasonography [24]; (3) thyroid nodule biopsy revealing a hyperplastic lesion or follicular adenoma, although, in the latter case, diagnostic surgery may be required to rule out a follicular carcinoma.…”

Thyrotoxicosis with concomitant thyroid cancer

“…MLS, defined as concomitant occurrence of autonomously functioning thyroid nodule (AFTN) and Graves' disease (Marine & Lenhart 1911), has the possibility of coexisting DTC as well (Scherer et al 2013). PTC and FTC occurred in MLS only reported by several cases by far (Scherer et al 2013, Sharma 2017.…”

“…DTCs found in or out of AFTN in MLS are really rare events (Valenti et al 1999, Scherer et al 2013, Sharma 2017, Lombardi et al 2018. The DTC happened in MLS may be related to the stimulation of TRAb or gene mutation such as BRAF V600E (Scherer et al 2013).…”

“…MLS with coexisting DTC is characterized by increased TRAb and RAIU, differentiating from Plummer's disease (Sharma 2017). Tumor manifests hypoecho in ultrasonography with or without microcalcification and presents 'hot' nodule in thyroid scan with comparatively lower but not suppressed uptake of the rest parenchymal tissue.…”

“…Tumor manifests hypoecho in ultrasonography with or without microcalcification and presents 'hot' nodule in thyroid scan with comparatively lower but not suppressed uptake of the rest parenchymal tissue. If ultrasonography indicates malignant tendency of the nodule, FNAC is essential to confirm the diagnosis (Scherer et al 2013, Sharma 2017.…”