Editorial review of ultrasound-guided fine-needle aspiration for solid thyroid nodules larger than 10 mm: correlation between sonographic characteristics at the needle tip and nondiagnostic results by Wu et al. Sebo review Thyroid nodules: team approach to a diagnostic and patient management challenge

In this issue of Endocrine, Wu and colleagues describe their sonographic findings in thyroid nodules that are linked to non-diagnostic (ND) fine-needle aspirations (FNA) [1]. Using a combination of standard ultrasound (US) and ultrasound elastography (USE), the authors evaluated 355 nodules (346 consecutive patients), all measuring C1 cm, focusing on echogenicity, vascularity, and degree of stiffness. The images were interpreted, and the FNA performed by a single sonographer with 15 years of thyroid imaging experience. One of the unique aspects of the study was aspirating (using a 23-guage needle) each thyroid nodule from two different locations based upon sonographic signals within the lesion. For statistical purposes, each pass was viewed independently. Only those cases in which both samples were classified as ND (defined as\6 follicular cell groups) was the FNA viewed as ND. This generated 710 samples for analysis, 81 (11.4 %) of which were ND. Tables 1 and 2 show the results, in univariate analysis, of the clinical and US/USE variables individually (Table 1) and in combination (Table 2) associated with an increased risk of a ND-FNA. Age, gender, and nodule size had no association. Echogenicity status was not linked to the risk of a ND-FNA although isoechoic and hypoechoic nodules trended toward a decreased and increased risk of a NDFNA, respectively. Conversely, vascularity status and elastic pattern both were statistically linked to a ND-FNA. In multivariate analysis (Table 3), nodules that were hypoechoic and avascular, and displayed a hard elastic pattern had the highest risk of a ND-FNA. As a pathologist for over 20 years in a busy thyroid FNA and surgical practice, the authors’ findings indirectly highlight an important fact, which is that an experienced sonographer is one of the three pillars by which patient care is optimized—the other two being an experienced pathologist and clinician. To state it another way, the antithesis of identifying US/USE findings linked to ND-FNA means that an experienced sonographer can enhance the likelihood of a diagnostic FNA by steering the needle away from those areas unlikely to generate sufficient cell numbers for cytologic interpretation [2]. The bad news is that even in the hands of the most experienced sonographer, the ND rate for thyroid nodules will never reach 0. At the time of presentation, an irreducible number of thyroid nodules will display a combination of cystic change and inelasticity. However, the good news is that, at least in our experience, we have found that the false negative rate of a diagnostic FNA (0.7 %), while statistically different in large databases, from the false negative rate of a non-diagnostic FNA (1.7 %), approaches clinical irrelevance—again, in the hands of experienced endocrinologists and radiologists [3]. Regardless, experienced sonographers can often tell with a high degree of certainty which nodules are worrisome enough to warrant surgical intervention, when the FNA is diagnostic, or reaspiration sooner than later, when the FNA is ND [2]. It is this experience, or more precisely, lack thereof, which, in my opinion, has led to the current confused state T. J. Sebo Surgical Pathology and Cytopathology, Mayo Clinic, Mayo Medical School, Rochester, MN, USA