Ectopic Mediastinal Thyroid Tissue Research Articles

FRI504 Ectopic Hyperactive Mediastinal Thyroid Tissue: A Case Report

Abstract Disclosure: C. Dimech: None. G. Jaiswal: None. A. Bhargava: None. Ectopic thyroid tissue is usually located along the normal path of the caudal migration of thyroid tissue during embryonic life. Substernal goiters are thought to occur by either the enlargement of ectopic mediastinal thyroid tissue (primary mediastinal goiter) or abnormal extension of thyroid issue into the superior mediastinum (secondary mediastinal goiter). Typically these goiters remain asymptomatic, and rarely result in hyperthyroidism or local compression of the surrounding area. We report a case of an 89-year-old Caucasian female with history of a multinodular goiter status post right hemithyroidectomy, who initially presented for subclinical hyperthyroidism. Further evaluation revealed negative thyroid stimulating antibodies. A thyroid ultrasound demonstrated a surgically absent right lobe, with a small heterogenous left lobe. A nuclear medicine radioactive iodine uptake and scan showed hypermetabolic residual thyroid tissue with a large area of increased radiotracer uptake projecting over the right anterior chest, concerning for ectopic thyroid tissue. A subsequent chest CT without contrast revealed an approximately 5 centimeter partially calcified anterior mediastinal/retrosternal mass. Given the patient’s age and co-morbidities, a decision was made to treat the hyperthyroidism with methimazole and monitor the ectopic tissue for worsening symptoms of compression. In cases with severe compressive symptoms, or difficult to treat hyperthyroidism, a surgical option must be considered. Presentation: Friday, June 16, 2023

Developing anterior mediastinum mass after orthotopic thyroidectomy: a case report

BackgroundEctopic thyroid tissue is a rare embryological aberration described by the occurrence of thyroid tissue at a site other than in its normal pretracheal location. Depending on the time of the disruption during embryogenesis, ectopic thyroid may occur at several positions from the base of the tongue to the thyroglossal duct. Ectopic mediastinal thyroid tissue is normally asymptomatic, but particularly after orthotopic thyroidectomy, it might turn out to be symptomatic. Symptoms are normally due to compression of adjacent structures.Case presentationWe present a case of a 66-year-old male submitted to a total thyroidectomy 3 years ago, due to multinodular goiter (pathological results revealed nodular hyperplasia and no evidence of malignancy), under thyroid replacement therapy. Over the last year, he developed hoarseness, choking sensation in the chest, and shortness of breath. Thyroid markers were unremarkable. He was submitted to neck and thoracic computed tomography, magnetic resonance imaging, and radionuclide thyroid scan. Imaging results identified an anterior mediastinum solid lesion. A radionuclide thyroid scan confirmed the diagnosis of ectopic thyroid tissue. The patient refused surgery.ConclusionsEctopic thyroid tissue can occur either as the only detectable thyroid gland tissue or in addition to a normotopic thyroid gland. After a total thyroidectomy, thyroid-stimulating hormone can promote a compensatory volume growth of previously asymptomatic ectopic tissue. This can be particularly diagnosis challenging since ectopic tissue can arise as an ambiguous space-occupying lesion.

Mucosa-associated lymphoid tissue (MALT) lymphoma developing in ectopic mediastinal thyroid tissue: a case report

BackgroundNormally located in the neck, ectopic mediastinal thyroid tissue consists of very rare ectopic thyroid tissue that does not connect to the thyroid gland. A patient with mucosa-associated lymphoid tissue (MALT) lymphoma that has developed in mediastinal thyroid tissue, to our best knowledge, has not been previously reported.Case presentationA 67-year-old woman presented with a superior mediastinal mass that was revealed by chest computed tomography (CT), an optional examination she hoped, during a medical checkup. Contrast-enhanced CT scan performed in our hospital for close examination confirmed the presence of a 2 × 1.3 cm poorly enhanced mass anterior to the trachea during the arterial phase. Magnetic resonance imaging depicted low signal intensity on T1-weighted images and high signal intensity on T2-weighted images. I-131 meta-iodobenzylguanidine did not accumulate in the mass. Serum levels of interleukin-2 receptor, catecholamine, and anti-acetylcholine receptor antibody were within the normal range. The mass was resected through a transverse neck incision for the diagnosis and treatment. The histopathological diagnosis of the specimen was ectopic mediastinal thyroid tissue associated with MALT lymphoma and chronic thyroiditis. Immunoglobulin heavy chain class switch recombination was identified. Fine-needle aspiration biopsy of the cervical thyroid showed chronic thyroiditis but not lymphoma. The patient’s postoperative thyroid function was normal. To date, the patient’s recovery has been uneventful, and she is being monitored without further treatment.ConclusionWe treated the patient with MALT lymphoma that developed in ectopic mediastinal thyroid tissue. This novel case illustrates a new differential diagnosis associated with ectopic mediastinal thyroid tissue.

Abstract #802971: Thyroid in My Chest?: Ectopic Mediastinal Thyroid Tissue with A Normally Located Thyroid Gland

Abstract #802971: Thyroid in My Chest?: Ectopic Mediastinal Thyroid Tissue with A Normally Located Thyroid Gland

Tiróide ectópica: A propósito de um caso clínico

The authors present a case report of an ectopic mediastinal thyroid tissue in a 45-year-old men sent to the the Pulmonology department of Hospital Entre Douro e Vouga to evaluate an enlargement of the mediastinum found in a routine radiogram requested by the family doctor. Some considerations on ectopic thyroid tissue, a rare finding in medical practice, are made, as well as the distinction between intrathoracic goiter and true ectopic thyroid.Rev Port Pneumol 2010; XVI (2): 345-352

Undifferentiated carcinoma arising from ectopic thyroid tissue in the anterior mediastinum

Summary A 78-year-old man was admitted with a tumor in the left anterior mediastinum that invaded the trachea and protruded into the lumen. Despite debulking with endobronchial laser followed by a tracheal stent and external radiotherapy, the tumor spread rapidly and extensively. Autopsy findings of the tumor indicated three distinct components: epithelial foci characterized by papillo-tubular structure, sarcoma-like spindle cells, and undifferentiated carcinoma. Immunohistochemical examination revealed that the epithelial foci were positive for thyroglobulin and thyroid transcription factor-1 whereas the spindle cells and undifferentiated carcinoma reacted with antibodies to α -smooth muscle actin and vimentin. Since the tumor was entirely separated from the cervical thyroid, we diagnosed it as undifferentiated carcinoma (spindle cell pattern) arising from ectopic mediastinal thyroid tissue. To our knowledge, this is the first report of undifferentiated carcinoma arising from ectopic thyroid tissue underscoring the need for correct diagnosis and early intervention of the highly malignant disease.

A Hyperthyroid Patient With Ectopic Mediastinal Thyroid Goiter Affected by Graves Disease

True ectopic mediastinal thyroid goiters are rare devel- opmental anomalies, accounting for less than 1% of all thyroid ectopies, whereas Graves disease in an ectopic mediastinal thyroid goiter has been reported only twice in the international literature. A 51-year-old female patient with poorly controlled hyperthyroidism, secondary to Graves disease was referred to our unit for thyroidec- tomy. A preoperative thyroid scan disclosed an ectopic thyroid goiter below the lower pole of the left thyroid lobe completely isolated from the cervical pretracheal thyroid gland. Intraopera- tively, an ectopic mass, macroscopically compatible to thyroid tissue, attached to the posterior surface of the left upper horn of the thymus gland, was found. The patient underwent total thyroid- ectomy followed by resection of the ectopic goiter. Histologic examination confirmed the thyroid nature of the ectopic tissue, showing findings compatible with Graves disease, in both the thyroid gland and the ectopic tissue. There were also loci of papillary carcinoma in the cervical thyroid gland. When a pretra- cheal thyroidectomy for symptomatic thyroid disease is planned, preoperative thyroid scan should be performed to detect possible ectopic thyroid tissue. The English literature reports that untreated ectopic mediastinal thyroid tissue can lead to failure to cure the hyperthyroidism in Graves disease or leave untreated coexisting malignancy in the ectopic tissue.