[How to treat a thyroid adenocarcinoma inside a branchial cyst]

The authors reported three cases of branchial cycts containing a thyroid adenocarcinoma. This rare condition imposed a search for the primary tumor. All complementary investigations remained negative as in the few cases reported in the medical literature. A loboisthmectomy for one and a total thyroidectomy for the two others, with cervical recurential neck dissection for all was carried out. Histological examination of the operative specimen after total blocking in paraffin helped discover microscopic foci of papillary carcinoma in the thyroid gland. These data justified this therapeutic attitude because the nature of the adenocarcinoma found in the branchial cyst is likely to be metastatic.