title: 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.
authors.affiliation: Discipline of Surgery, University Hospital Galway, Galway, Ireland. Mayoor18@yahoo.co.uk.
authors.forename: Nithiananthan
authors.initials: N
authors.lastname: Mayooran
authors.affiliation: Discipline of Surgery, University Hospital Galway, Galway, Ireland.
authors.forename: Peadar S
authors.initials: PS
authors.lastname: Waters
authors.affiliation: Discipline of Surgery, University Hospital Galway, Galway, Ireland.
authors.forename: Tahir Y
authors.initials: TY
authors.lastname: Kaim Khani
authors.affiliation: Discipline of Surgery, University Hospital Galway, Galway, Ireland.
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Kerin
authors.affiliation: Discipline of Surgery, University Hospital Galway, Galway, Ireland.
authors.forename: Denis
authors.initials: D
authors.lastname: Quill
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D044963:Biopsy, Fine-Needle / Q000706:statistics & numerical data*; D019468:Disease Management; D005260:Female; D005629:Frozen Sections / Q000706:statistics & numerical data*; D006801:Humans; D008297:Male; D008875:Middle Aged; D011300:Preoperative Care / Q000379:methods; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D013959:Thyroid Diseases / Q000473:pathology; D013961:Thyroid Gland / Q000473:pathology* / Q000601:surgery; D013964:Thyroid Neoplasms / Q000473:pathology* / Q000601:surgery; D016606:Thyroid Nodule / Q000473:pathology / Q000601:surgery
keywords: FNAC; Frozen sections; Thyroid cancer; Thyroid nodules; Thyroid surgery