A case of papillary carcinoma arising in ectopic thyroid tissue within a branchial cyst with neck node metastasis.

We describe the interesting case of a young man who presented with a lateral neck node that was diagnosed as a branchial cyst. Histopathology of the excised node revealed that a papillary carcinoma was located within thyroid tissue, which in turn was located within a branchial cyst. A total thyroidectomy with local lymph node clearance was performed. Histology identified a normal thyroid gland, but a papillary carcinoma in one of the excised lymph nodes was consistent with a metastasis. To our knowledge, this is only the second reported case of a thyroid carcinoma arising in ectopic thyroid tissue that metastasized in the neck.