Sonographic detection of intrathyroidal branchial cleft cyst: a case report.

We report here on an extremely rare case of an intrathyroidal branchial cleft cyst. Intrathyroidal branchial cleft cyst is rare disease entity and it has nonspecific findings on sonography, so the diagnosis of the lesion is very difficult. However, during aspiration, if pus-like materials are aspirated from a thyroid cyst, we should consider the possibility of intrathyroidal branchial cleft cyst in the differential diagnosis.