Ectopic papillary thyroid carcinoma in the mediastinum without any tumoral involvement in the thyroid gland. A Case report.

Ectopic thyroid tissue results from abnormal embryologic development and migration of the thyroid gland. True malignant transformation in ectopic thyroid tissue is extremely rare and is always diagnosed after surgical excision of the lesion by pathology examinations. There are well-documented cases of ectopic thyroid cancer while primary tumoral lesion occurs in the orthotopic thyroid, but only rare cases of ectopic PTC without any evidence of occult thyroid cancer in the orthotopic thyroid or cervical lymph nodes have been reported.