Endocrine Abstracts

Introduction: Ultrasound (US) is an extremely sensitive examination for thyroid nodules. Fine needle aspiration (FNA) cytology samples taken with ultrasound guidance, increases accuracy and reduces rates of unsatisfactory samples¹. In addition, the immediate assessment of the sample for adequacy by onsite cytopathology is shown to reduce inadequacy rates by most reports².

Aim: The aim of this study was to compare the inadequacy (Thy1) rates between US guided FNA with onsite histopathology and palpation guided (Free-hand) FNAs.

Methods: Retrospective review of all FNAs performed during five years period between 2008 and 2012.Data were collected from the pathology department laboratory and the radiology computerised systems.

Results: Five hundred and sixty seven thyroid FNAs were performed on 433 patients during this period. The cytological diagnoses were as follows: Thy1 (non-diagnostic) in 63 (11.1%) cases, Thy2 (benign) in 424 (74.8%) cases, Thy3 (follicular lesion/neoplasm) in 54 (9.5%) cases, Thy4 (suspicious for malignancy) in 9 (1.6%) and Thy5 (malignant) in 17 (3%) cases. Out of 531 cases were the guidance method was documented, 423 (79.7%) were US guided with onsite cytopathology evaluation and 108 (20.3%) were free-hand. Inadequacy rate (Thy1) was significantly lower in the US guided FNA (37/423, 8.7%) compared to the free-hand aspirates (17/108, 15.7%), (P<0.05).

Conclusion: FNAs done under US guidance combined with onsite cytopathology have significantly lower in-adequacy rates compared to free-hand FNA.This method should be used in all cases to improve adequacy and reduce patient distress and cost.

References: 1. Peros P, et al. Guidelines for the management of thyroid cancer. Clinical Endocrinology, 2014; 81: 1–12.

2. Poller D N, et al. Thyroid FNAC cytology: can we do it better? Cytopathology 2008 Feb; 19(1):4–10.