Thyroid diagnostic modalities (fine needle aspiration and core needle biopsy) with histology correlation: a tertiary centre experience

• Published in: Journal of clinical pathology Vol. 75; no. 9; pp. 620 - 626
• Main Authors: Appukutty, Sona J, Paterson, Anna, Patel, Nishant S, Duckworth, Adam, Chan, James, O'Donovan, Maria, Marker, Alison J
• Format: Journal Article
• Language: English
• Published: London BMJ Publishing Group Ltd and Association of Clinical Pathologists 01.09.2022; BMJ Publishing Group LTD
• Subjects: Accuracy; Biopsy; Cellular biology; cytological techniques; diagnostic techniques and procedures; Histology; image-guided biopsy; Lymphoma; Metastasis; Original research; Pathology; Statistical analysis; Surgery; Thyroid cancer; thyroid gland; thyroid neoplasms; Tumors; Ultrasonic imaging
• ISSN: 0021-9746; 1472-4146
• DOI: 10.1136/jclinpath-2020-207275

AimsTo determine the proportion of thyroid fine needle aspiration (FNA) and core needle biopsy (CNB) cases reported at a single institute into each UK Royal College of Pathologists (RCPath) Thy1-5 and local T category, respectively. Where subsequent histology was available, malignancy rates, sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) and diagnostic accuracy were compared for both procedures.Methods1591 FNAs (2010–2018) and 514 CNBs (2013–2018) cases were identified, together with paired histology excision specimens.ResultsThe FNA samples were classified as: Thy1: 45.3%, Thy2/Thy2c: 22.1%, Thy3a/Thy3f: 28%, Thy4: 1.6% and Thy5: 3%; while the CNB were classified as: T1: 7.2%, T2: 22.4%, T3 59.3%, T4: 1% and T5: 10.1%. Comparison of FNA and CNB classified as Thy5/T5 showed a 100% risk of malignancy (ROM), sensitivity (98% vs 100%), specificity (14.1% vs 12.1%), PPV (29.4% vs 29.4%), NPV (94.9% vs 100%) and accuracy (36.5% vs 35.6%), respectively, for a diagnosis of malignancy. ROMs for other categories were: Thy1/T1 (9% vs 6.7%), Thy2/T2 (5.1% vs 0%), Thy3/T3 (17.5% vs 18.4%) and Thy4/T4 (73.3% vs 100%).ConclusionsThe proportion of cases in each RCPath Thy category has remained relatively stable during the 9-year study period, with the exception of the Thy3a category, which has increased over time. This finding is in line with other more recent reports in the literature and the proportion of T3 cases in the CNB group. The proportion of Thy2/Thy2c cases has also reduced over time, reflecting a local change in the triaging protocol for probable benign lesions. Both FNA and CNB showed comparable performance in our study.