Mediastinal ectopic thyroid tissue as diferential diagnostic problem: A case report

Stefan Stojanoski; Milorad Bijelović; Branislava Ilinčić; Dejan Vučković; Duško Kozić; Milica Medić Stojanoska

doi:10.2298/VSP200207058S

Stefan Stojanoski University of Novi Sad, Faculty of Medicine, Novi Sad, Serbia; Oncology Institute of Vojvodina, Center for Imaging Diagnostics, Sremska Kamenica, Serbia
Milorad Bijelovic University of Novi Sad, Faculty of Medicine, Novi Sad, Serbia Institute for Pulmonary Diseases of Vojvodina, Thoracic Surgery Clinic, Sremska Kamenica, Serbia
Branislava Ilincic University of Novi Sad, Faculty of Medicine, Novi Sad, Serbia; Clinical Center of Vojvodina, Center for Laboratory Medicine, Novi Sad, Serbia
Dejan Vuckovic University of Novi Sad, Faculty of Medicine, Novi Sad, Center for Pathology and Cytology, Institute for Lung Diseases of Vojvodina, Sremska Kamenica, Serbia
Duško Kozić University of Novi Sad, Faculty of Medicine, Novi Sad, Center for Imaging diagnostics, Oncolgy Institute of Vojvodina, Sremska Kamenica, Serbia
Milica Medic Stojanoska University of Novi Sad, Faculty of Medicine, Novi Sad, Clinic for Endocrinology, Diabetes and Metabolic Diseases, Clinical Center of Vojvodina, Novi Sad, Serbia

DOI: https://doi.org/10.2298/VSP200207058S

Keywords: congenital abnormalities;, diagnosis, differential;, histological techniques;, mediastinal neoplasms;, thyroid gland

Abstract

Introduction. Mediastinal ectopic thyroid tissue (ETT) represents a rare entity. Clinically, it can manifest with thyroid gland dysfunction or with symptoms and signs caused by a compressive effect on the surrounding structures, but in most cases it is an asymptomatic condition and incidental finding. All pathologic processes, including malignancy that can occur in the orthotopic thyroid gland can also develop in the ETT. Case report. We presented a case of a 17-year-old female with incidentally found mediastinal ETT. Besides ETT, the patient had an orthotopic thyroid gland and was euthyroid. During follow-up, mild compressive symptoms developed. Magnetic resonance imaging examination showed a non-significant increase of the mediastinal mass volume, but due to its morphological changes, a suspicion of another etiology was raised. A discrepancy between the positive technetium-99m pertechnetate and negative 131 iodine radionuclide imaging of the mediastinal mass was highly suspicious for malignancy. Surgery was performed and the pathologist confirmed that it was a colloid goiter in the mediastinal ETT. Conclusion. Mediastinal ectopic thyroid tissue should be taken into account in the differential diagnosis of the mediastinal tumor mass. An increase in the size of the mediastinal ETT, development of compressive symptoms or suspected malignant alteration require surgical treatment.

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