Unilateral right thyroid swelling with contralateral left mediastinal mass of benign ectopic thyroid tissue: a rare case report.

Introduction and importance: Ectopic thyroid is a very rare developmental anomaly with difficult diagnostic challenges, especially when located away from its normal anatomical pathway of development and descent. The coexistence of a unilateral thyroid enlargement with a mass in the thoracic region is very rare and can resemble malignancies and tumors complicating the process of diagnosis and management. Case presentation: A 44-year-old female presented with a unilateral right thyroid swelling, with further investigation revealing a left mediastinal mass. Initial imaging and biopsy raised concerns about possible malignancy. However, a surgical biopsy confirmed benign ectopic thyroid tissue. The patient underwent total thyroidectomy and excision of the mediastinal mass, recovering without complications. Clinical discussion: This case reports a rare coexistence of thyroid swelling and ectopic thyroid in the mediastinum. An extensive diagnostic protocol is mandatory to exclude any potential malignancies. Careful surgical management is required for optimal outcomes and the long-term well-being of the patient. Conclusion: This case report emphasizes the significance of considering ectopic thyroid as a differential diagnosis of mediastinal masses. This case report presents information that not only helps to prevent misdiagnosis but also guide on the suitable treatment and management.