ES14 *CAN CYTOLOGY EXCLUDE THYROGLOSSAL DUCT CYST PAPILLARY CARCINOMA?

Abstract

Background: Thyroglossal duct cysts (TDC) are the commonest midline neck mass. They occur in approximately 7% of the population. Thyroglossal duct carcinoma is uncommon but is reported in 1% of all thyroglossal cysts. Sistrunk's procedure is the accepted treatment for TDC.Aims: The aims of this study were: to determine the incidence of Papillary Thyroid Cancer in TDC; to compare cytology from the cyst and final histopathology; and to assess the adequacy of Sistrunk's procedure.Method: A retrospective analysis of prospectively collected data of all TDC operations performed by the unit within a 15 year period, 1993–2008, was undertaken.Results: There were 39 patients; 14 males and 25 females, of median age 40 (range 17–79) years. The main presenting symptom was a neck lump, ranging from 1 week to 17 years and mainly in the midline (33/39). The imaging modality of choice was ultrasound of the neck which correctly identified a cystic structure likely to be a TDC in the neck in 31/33 cases (94%). Fine needle aspirate cytology (FNAC) in 24 patients predicted a benign TDC with a sensitivity of 95.6% and a specificity of 100%. Papillary Thyroid Cancer occurred in four TDC, an incidence of 10%. All patients had a Sistrunk's procedure, from which there were no recurrences. Two of the Papillary Thyroid Cancer patients underwent total thyroidectomy. There were six minor complications, a rate of 15%.Conclusion: The incidence of Papillary Thyroid Cancer in TDC was 10% in this series. The remaining lesions were benign and FNAC correctly predicted this with a sensitivity of 95.6%. Sistrunk's procedure is adequate treatment with minimal complications and no recurrences.