Papillary thyroid carcinoma in a branchial cleft cyst

While most BCCs are benign, PTC can very rarely present within BCC. Metastatic PTC with a necrotic lymph node is often misdiagnosed as BCC, both radiographically and histologically. Since PTC arising as a primary tumor from ectopic thyroid tissue within a BCC is extremely rare, total thyroidectomy should be considered even in patients with radiographically normal thyroid to rule out micropapillary primary thyroid tumors. A thyroglobulin assay from the needle washout of a fine-needle aspiration of a BCC may help preoperatively identify differentiated thyroid cancers. Micropapillary thyroid cancers (<1 cm) are usually indolent, but some may show nodal metastases and clinical progression.