An Uncustomary Branchial Cleft Cyst Presentation With Associated Autoimmune Thyroiditis.

Branchial cleft cyst is an embryogenic anomaly of branchial apparatus usually occurring in the lateral aspect of the neck. Very few cases of intrathyroidal cystic lesion of branchial cleft have been reported in English literature so far. The patient was a 42-year-old female who presented to the Otorhinolaryngology department with anterior neck mass. The serology revealed elevated antibodies to thyroglobulin and thyroid peroxidase. Fine needle aspiration done in an outside hospital was reported as an epidermal inclusion cyst. Radiology examination of the neck was suggestive of infected fourth branchial cleft cyst. Left hemithyroidectomy was done. On histopathology examination, branchial cleft cyst within the thyroid parenchyma exhibiting features of autoimmune thyroiditis and secondary degenerative changes was noted. This rare case is reported to emphasize multiple-site fine needle aspiration in heterogenous thyroid lesions along with radiological correlation for correct diagnosis and appropriate treatment.