Ectopic mediastinal thyroid removed by U-VATS approach. A case report.

Introduction: Ectopic thyroid tissue is a rare entity, and accounts for approximately 1% of all mediastinal tumours. It is a differential diagnosis of the mediastinum tumors or metastatic deposits from an orthotopic gland, as well as other benign or malignant masses. Although most cases are asymptomatic and discovered incidently by imaging, symptoms related to tumor size and its compression of adjacent structures may also appear which necessites explorations and lead to diagnosis.

Case Presentation: This is a 59-year-old women, followed for glaucoma and operated for bilateral congenital cataract reffered to our structure by the service of pnemology for a right laterotracheal mediastinal mass. The patient presented respiratory symptoms over four months, and the physical examination found patient in good condition with PS 0 and normal vital signs, a poor oral health was noticed. The CT scann showed a left basal opacity and a right laterotracheal mediastinal mass at the upper right mediastinum, pushing forward the superior vena cava and compressing the trachea on the contralateral side, with well-defined borders and without signs of infiltration of adjacent structure. The brochoscopy was perfomed which showed the yellowish granulous aspect and the pathophysiology revealed a pulmonary actinomycosis. The patient was treated with antibiotic based on parenteral infusion of penicillin G at 20 million / day for 6 weeks relayed by oral administration of 3 g / day for 3 months with a good response and the left basal opacity disappeared on the CT control but the mediastinal mass persisted. After multidisciplinary concertation, the mediastinoscopy was perfomed and has revealed an ectopic thyroid which was removed by Uniportal Videoassisted Thoracoscopic Surgery (U-VATS) approach.

Discussion: The first case of ectopic thyroid gland was described by Hickman in 1869, since a few cases have been reported by the literature. Its prevalence is about 1 per 100 000-300 000 people, rising to 1 per 4000-8000 patients with thyroid disease. The main techniques indicated in the management of undetermined lesions of the anterior mediastinum, are midline exploratory sternotomy, anterior lateral thoracotomy and VATS. U-VATS has demonstrated its feasibility and safety compared to conventional techniques by several advantages.

Conclusion: Ectopic mediastinal thyroid is an unusual presentation of thyroid pathology. Complete surgical resection remains a therapeutic and a key diagnosis. The aim of this study is to prouve the feasibility, efficiency and efficacity of U-VATS approach as minimally invasive thoracic surgery for mediastinal mass resection.