Thy3 cytology: what to do next?

Cytological analysis of thyroid fine needle aspiration (FNA) is aided by the 'Thy' classification. However, there is often confusion surrounding the management of patients with a Thy3 classification. A subdivision of Thy3 has been created to help reduce this dilemma but its use within the UK appears to by infrequent. This paper analyses the management of patients with Thy3 cytology from FNA of a thyroid nodule in a UK case series and reviews the relevant literature. It also describes the results of a survey of selected UK ENT departments on the use of the Thy3 classification and its subdivisions.

A retrospective analysis of a case series of patients was undertaken. In addition, a telephone survey of local/regional pathology departments was conducted to assess the utilisation of the Thy classification and to assess the awareness and usage of the Thy3 subdivisions.

A total of 39 Thy3 results (11 males, 28 females) were identified from 2007 to 2009. Of these, 24 patients went on to have surgery, 8 had a further FNA, 2 had a Tru-cut biopsy and 5 were lost to follow-up. Eleven (28.2%) patients were subsequently diagnosed with a thyroid malignancy. The survey identified that none of the departments had adopted the Thy3 subclassifications and only 40% were aware of them.

Thy3 results from thyroid FNA have a significant risk of malignancy but there remains confusion surrounding their management. This district general hospital has adopted and recommends the use of the Thy3 (i) and Thy3 (ii) subdivisions in order to assist decision-making and avoid delays in treatment or unnecessary surgery.