Metastatic Papillary Thyroid Microcarcinoma Presenting as a Branchial Cleft Cyst in Young Female.

Though aetiology of lateral neck masses is complex, branchial cleft cyst is the second most common congenital lesions of the neck next only to thyroglossal duct cysts. Rarely ectopic thyroid tissue within a branchial cleft cyst may develop into primary papillary carcinoma, and even more rarely it may harbour metastases of primary thyroid papillary carcinoma. We report a rare case of lateral cystic neck mass in a 24-year-old female patient diagnosed as metastatic PTC. The patient was diagnosed after she underwent surgical excision of branchial cleft cyst. Later prospectively the patient underwent total thyroidectomy which revealed papillary thyroid micro invasive carcinoma.