Mediastinal teratoma presenting as a cervical tumor: images

Benign extra-gonadal germ cell tumors, known as teratoma or dermoid cysts, are commonly found in the anterior mediastinum in association with the thymic gland. This association is due to their common site of embryological origins, from the third and the fourth pharyngeal pouches. Since it is not unusual to find normal thymic tissue in the neck, germ cell tumors arising from here will present as a cervical tumor. We submit the typical images of one such tumor in a young adult. Intraoperatively, the tumor was well encapsulated and was connected to the mediastinal thymus by a long pedicle of thymic tissue. It was not related to the thyroid gland unlike a primary cervical teratoma. We present these typical images of a mediastinal dermoid in this unusual cervical location. The differential diagnoses to be considered clinically are primary cervical teratomas, thyroid tumors, lymph nodal pathologies, and branchial cyst.