Branchial fistula: a rare presentation.

Remains of cervical sinus of His may persist as a branchial cyst. A branchial sinus is formed when 2nd branchial arch fails to meet the 5th pharyngeal arch. Peak age for presentation of cysts is in the third decade and that of the congenital sinuses and fistulae is at birth. Rarely a branchial sinus is found to have an internal opening as well, thus forming a true branchial fistula. We present a case of true branchial fistula with external opening on the lateral side of neck and internal opening near the lower pole of tonsil.