In our centre, thyroid core-biopsy (CB) has replaced fine needle aspiration biopsy (FNAB) in the study of thyroid nodules because its better accuracy. International guidelines recommend repeating the FNA in cases of inadequate or insufficient first specimen, but nothing is published about the case in failed CB.
Objective: To study the differences between nodules with inadequate and diagnostic thyroid Core Biopsy and the accuracy of repeating a CB after a previous inadequate result.
Methods: Methods of 3.972 CB performed along ten years (20052015) in 3.384 patients, 139 (3.5%) were considered inadequate for diagnosis, due to insufficient tissue, intense fibrosis or bad processing. CB was performed using an 18G spring-loaded device. We standardized four diagnostic categories: insufficient, benign, microfollicular proliferation and malignant.
Results: Patients with inadequate CB were younger than the patients with diagnostic biopsies (53.7 vs 57 y-o; p: 0.012). Mean nodule diameter was smaller in insufficient CB (20.6 mm vs 25.9 mm), isthmic localization was more frequent (19.5% vs. 7%). and they were less frequently predominantly solid (50% vs. 70.5%). In 22 cases, simultaneous FNA were conducted in predominantly cystic nodules, eleven of them diagnostic in cytological study, all of them benign.
In 51 cases a second CB was performed being diagnostic in 48 cases (94.1%), 45 of them hyperplasic tissue, 2 follicular proliferations and 1 papillary thyroid cancer. Surgery was performed in 10 cases which confirmed the diagnosis in the last 3 cases, two follicular adenomas and one PTC, and in another 7 benign lesions.
Conclusion: Second CB has 94.1% of successful sampling. Most nodules with non-diagnostic initial CB are benign. Combination of 2 thyroid CB allows a diagnosis in nearly all thyroid nodules.