Accessory thymus in posterior mediastinum

Abstract

Presence of thymus in the normal position as well as in the posterior mediastinum is an unusual phenomenon. We report here a case of posterior mediastinal mass in a 20-month old male child who presented with dysphagia and dry cough. Investigations revealed it to be a solid posterior mediastinal mass, suspected to be either lymphoma or a neuroblastoma. Excision of the mass followed by histopathologic examination revealed the mass to be a normal thymus. This case indicates that a benign mass, an accessory thymus, though rare, can be located in the posterior mediastinum and cause symptoms similar to solid mediastinal tumors.

Persistent Enlarged Thymus in an Adult Human Cadaver

“…The bilateral primordia of thymus develop in the region of superior neck from the endoderm of third phyrangeal pouch 5 in early fetal life and reach final destination in the mediastimun by progressive descent. The thymus is attached to the thyroid by thyrothymic ligament 6,7 . There are limited reports on variations in thymic anatomy.…”