Fine needle aspirationcytology（FNAC）in the diagnosis of thyroid microcarcinoma

It is often necessary to judge whether to use fine needle aspiration cytology（FNAC）on thyroid nodules ≤ 1 cm at present. In our hospital, we have developed an original FNAC instrument for improving the diagnostic accuracy and safety of FNAC, and have been using this instrument since 2009. We have already reported on the usefulness of this instrument. In this study, we investigated the effects of FNAC using this instrument on thyroid nodules ≤ 1cm. A retrospective chart review was performed on 312 specimens of 265 patients who underwent FNAC on thyroid nodules ≤ 1 cm between January 2014 and December 2015. We investigated the inappropriate rate of all specimens, operator, tumor site, presence or absence of calcification, and presence or absence of cysts. The inappropriate rate of all specimens was 8.3％; the investigated inappropriate rate did not differ among operators, site of tumor, or properties of tumor. The inappropriate rate of thyroid nodules ≤ 1 cm was improved by the original FNAC instrument and procedure.