FNAC and frozen section correlations with definitive histology in thyroid diseases

Abstract

The ability to diagnose thyroid cancers pre-op or intra-operatively by fine needle aspiration cytology (FNAC) or frozen section (FS) leads to the delivery of appropriate one-stage surgical management. We aim to study the concordance and discordance of FNAC and FS with final histology in thyroid pathologies. All thyroid procedures from 2007 to 2011(n = 423), involving FNAC and or frozen section in their management pathway were included. FNAC (n = 159) were classified in a five-tier system (Nondiagnostic, Benign, Atypical, Suspicious or Malignant). FS (n = 128) were classified as inconclusive, benign, suspicious or malignant. FNAC and FS were correlated with final histopathology. 159 out of 423 patients had FNAC (PPV 85.1 %), 26 inadequate specimens noted, benign cytology 57, atypical (n = 23), follicular neoplasm (n = 27), suspicious for malignancy (n = 16) and malignant 11. 13 out of 27 follicular neoplasm and 6 of atypical FNAC cases showed malignancy in their final histopathology. Frozen sections; total of 126 patients had intra-operative frozen section biopsies performed. Overall 105 out of 126 FS biopsies were benign; 21 malignancies detected intraoperatively. Three FS were inconclusive and reported benign in final histopathology. Overall, FNAC demonstrated a PPV of 66.6 % and NPV of 84.6 %. FS demonstrated PPV and NPV of 76.1 and 85.7%, respectively. In conclusion, FNAC is considered as the best modality to triage the thyroid nodule pre-operatively. Atypical and follicular neoplasm cytology categories warrant further clinical assessment and close follow-ups when appear benign. The intra-operative frozen sections are helpful to perform a one-stage operation for suspicious thyroid lesion. This study also highlights the recognised limitation of intra-operative frozen section analysis of thyroid neoplasia.

Malignancy Rate in Thyroid Nodules with Atypia or Follicular Lesion of Undetermined Significance

“…[28][29][30] However, several recent series report very low sensitivities, ranging from 22% to 51%. 31,32 In a recent review, Najah and Tresallet 33 concluded that FSs contributed little to the diagnosis of undetermined thyroid nodules due to their low sensitivity and high false negative rates. They suggested that tumor capsular invasion, which is the hallmark to diagnose malignancy, could not be evaluated on FSs, and was only possible on permanent sections.…”

Utility of intraoperative frozen sections of thyroid tissue in the age of molecular testing

“…FS only altered the initial surgical plan in 7.5% cases. This compares with a rate of 0‐62% in the literature, 9‐20 with studies significantly affected by patient factors, surgeon preference and selection bias. The only preoperative measure that significantly correlated with a “positive” FS in our cohort was an USGFNA result of “suspicious for malignancy” (Thy 4/Bethesda V).…”

“…An extensive amount of literature has been published on the utility of intraoperative FS and its correlation to preoperative USGFNA results. The results and conclusions of these papers are largely influenced by their cohort characteristics and pathology 9‐20 . Our institution represents a high‐volume tertiary care centre with dedicated endocrine pathologists.…”

Perioperative diagnostics of patients referred for radioiodine therapy of differentiated thyroid carcinoma: referral center experience in an iodine-insufficient country

“…Mayooran et al showed a clear correlation between FNB and frozen section with the definitive histology of thyroid cancer and concluded that “FNAC [abbreviation of: fine-needle aspiration cytology] is considered as the best modality to triage the thyroid nodule preoperatively,” and that “the intraoperative frozen sections are helpful to perform a one-stage operation for suspicious thyroid lesions” [ 13 ]. It is therefore unfortunate to notice that the present investigation of clinical practice in perioperative diagnostics in thyroid cancer patients reveals quite similar numbers as in the aforementioned previous studies [ 2 ].…”