Effects of nodule characteristics on sampling number and duration of thyroid fine-needle aspiration biopsy: size does not matter, but cystic degeneration ratio does

Abstract

Background Ultrasound-guided fine needle aspiration biopsy (FNAB) of thyroid nodules, though the most accurate method to rule out malignancy, still has an inherent risk of yielding non-diagnostic specimens despite immediate assessment of specimen adequacy by an on-site cytopathologist. Purpose To evaluate the effects of nodule volume and extent of cystic degeneration on total biopsy time and number of aspirations required for obtaining an adequate specimen. Material and Methods A total of 510 patients underwent FNAB by a single radiologist accompanied by a cytopathologist who immediately assessed each sample for specimen adequacy. All sampled nodules were single and had one maximum diameter > 10 mm. Nodule volumes and cystic degeneration ratios were calculated prior to the intervention. Aspirations were repeated until the cytological material was deemed adequate by the cytopathologist; the number of aspirations and total biopsy time were then recorded. Results Nodule volumes did not have significant effect on neither number of aspirations necessary for achieving specimen adequacy ( P > 0.05) nor total biopsy time (r = -0.148 with P = 0.001). Predominantly cystic nodules, compared to predominantly solid nodules, required more sampling per nodule (4.58 ± 1.11 vs. 3.44 ± 1.19 aspirations, P = 0.001) and longer total biopsy time (16.40 ± 6.19 vs. 11.15 ± 6.18 min, P = 0.001). Conclusion Predominantly cystic nodules require allocation of more time for biopsy. To ensure specimen adequacy when immediate specimen evaluation by an on-site cytopathologist is not possible, four samples from predominantly solid nodules and five passes through predominantly cystic nodules are required.

Optimized algorithm in solid thyroid nodule elastography

“…Another research study also indicated that partially cystic nodules had higher elasticity modules than solid ones in both shear wave elastography (SWE) and strain elastography although the cause remains unknown (16,17). In addition, it was reported by Cengic et al (18) that the success rate of fine-needle aspiration (FNA) was lower and total biopsy time of FNA was longer in predominantly cystic nodules than that in predominantly solid ones. Furthermore, Gu et al (19) and Chan et al (20) reported that the risk of being malignant in solid or predominantly solid thyroid nodules was higher than that in the cystic or predominantly cystic nodules.…”

Conditions associated with the need for additional needle passes in ultrasound‐guided thyroid fine‐needle aspiration with rapid on‐site pathology evaluation

“…The effect of various factors on the adequacy of US‐guided thyroid FNA has been investigated broadly in the past few years. Some studies suggest that the experience of the operator plays a significant role while other studies discuss the impact of nodule characteristics, sampling technique, needle size, and on‐site evaluation 7‐11 . In our study, to further investigate the impact of nodule size and composition, we removed the effect of potential confounding factors including the operator experience, needle size, sample preparation, and adequacy assessment by analyzing FNAs performed by a single experienced radiologist using a 25‐G needle, on‐site adequacy assessments performed by an experienced cytopathologist or cytopathology fellow, and slide preparation performed by a cytotechnologist or cytopathology fellow.…”

Needle Biopsy Adequacy in the Era of Precision Medicine and Value-Based Health Care

“…Also, lesions with a cystic component may require more sampling to achieve sufficient yield. 125 Further, molecular heterogeneity, such as intratumor mutational heterogeneity, may be present even when cytologic appearances with light microscopy are relatively homogenous.…”