AB087. 192. Branchial cleft cyst—really?

Background: Branchial cleft cysts may be difficult to distinguish from malignant cystic lesions of the lateral neck. While fine needle aspiration cytology (FNAC) has a sensitivity of 95% in diagnosis of solid head and neck lesions, the false negative rate in cystic lesions is as high as 67%. Our aims were to determine the incidence of malignancy in clinically diagnosed branchial cleft cysts and secondly, to determine the accuracy of preoperative investigations in their detection.

Methods: A single-centre retrospective study of all patients who underwent suspected branchial cleft cyst excision between July 2011 & July 2017 was carried out. Clinical records, pre-operative imaging, FNAC and operative histology were reviewed.

Results: Of the 30 patients included, malignant disease was identified on operative histology in 9 (30%). Four patients were diagnosed with primary lymphatic malignancy and 5 with metastatic nodal disease (2 nasopharyngeal SCC, 3 papillary thyroid carcinoma). Mean age of those with malignant diagnosis was 46.8±19.08 years, compared with 32.75±15.21 years in those with a confirmed branchial cleft cyst. Eight patients had undergone preoperative FNAC, which demonstrated benign cytology in 5 (66.6%). Preoperative imaging did not detect obvious malignant lesions in any of the 9 patients, however 6 were noted to have generalised cervical lymphadenopathy.

Conclusions: Malignant disease should be considered in patients presenting with suspected branchial cleft cysts. Factors increasing likelihood of malignancy include increasing age and presence of lymphadenopathy on imaging. Negative FNAC does not out rule the possibility of malignant disease.

Keywords: Branchial cyst; malignancy; incidence