Abnormal radioiodine uptake on post-therapy whole body scan and sodium/iodine symporter expression in a dermoid cyst of the ovary: report of a case and review of the literature

In patients affected by differentiated thyroid cancer, the whole-body scan (WBS) with 131-radioiodine, especially when performed after a therapeutic activity of131I, represents a sensitive procedure for detecting thyroid remnant and/or metastatic disease. Nevertheless, a wide spectrum of potentially pitfalls has been reported. Herein we describe a 63-year-old woman affected by follicular thyroid cancer, who was accidentally found to have an abdominal mass at post-dose WBS (pWBS). pWBS showed abnormal radioiodine uptake in the upper mediastinum, consistent with lymph-node metastases, and a slight radioiodine uptake in an abdominal focal area. Computed tomography revealed an inhomogeneous mass in the pelvis, previously unrecognized. The lesion, surgically removed, was found to be a typical dermoid cyst of the ovary, without any evidence of thyroid tissue. By immunohistochemistry, a moderate expression of the sodium-iodine symporter (NIS) was demonstrated in the epithelial cells, suggesting a NIS-dependent uptake of radioiodine by the cyst.

An uncommon case of Marine-Lenhart syndrome / Um caso incomum de síndrome de Marine-Lenhart

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.

O termo “síndrome de Marine-Lenhart” descreve a associação da doença de Graves e nódulos tireoidianos de funcionamento autônomo (AFTN), como no adenoma tóxico ou bócio multinodular tóxico. As duas doenças podem coexistir ou podem estar presentes em diferentes momentos no mesmo paciente. Na literatura, existem muitos relatos sobre o desenvolvimento da doença de Graves após radioiodoterapia para AFTN, mas muito poucos dados podem ser encontrados em relação ao aparecimento de AFTN após radioiodoterapia para doença de Graves. Descrevemos o caso de uma paciente do sexo feminino com doença de Graves que realizou com sucesso o tratamento com iodo radioativo, com a normalização da função da tireoide. Três anos depois, uma análise bioquímica e um exame de ultrassonografia identificaram o aparecimento de um nódulo na tireoide que progressivamente aumentou de tamanho. A cintilografia com 99mTc-pertecnetato revelou uma captação ávida no lóbulo direito, correspondente à lesão nodular, consistente com uma AFTN.