Hashimoto’s Thyroiditis Presenting as a Retrocaval Mass

A 49-year-old lady presented to the OPD with complaints of cough associated with breathlessness for 4 days and one episode of hemoptysis. She also had an anterior neck swelling for the past 2 years. The swelling did not cause any dysphagia. On examination, the patient had a smooth, diffusely enlarged swelling in the anterior region of her neck. There was no lymphadenopathy. She was found to be euthyroid by blood investigations. An anti-thyroperoxidase titer was sent because of the thyroid swelling, which was elevated. FNAC of the swelling showed benign hyperplasia of thyroid-Bethesda stage 2. Chest X-ray showed a widened mediastinum, and a contrast CT showed two well-defined heterogenous mediastinal lesions with central areas of necrosis located posterior to the superior vena cava. A Technetium-99 m pertechnetate radionucleotide scan did not show any uptake. She was planned for an anterior thoracotomy for an excision biopsy of the mass. Histopathology revealed thyroid tissue with heavy lymphocytic infiltration suggestive of Hashimoto’s thyroiditis. No cases of ectopic Hashimoto’s thyroiditis in the middle mediastinum with elevated Anti-TPO have been reported. Here, we report a case of ectopic thyroid tissue at a very unusual location behind the superior vena cava showing features of Hashimoto’s thyroiditis.