Traditional teaching dictated that patients with recurrent thyroid cysts undergo excision owing to a 12% risk malignancy. Ultrasound evaluation now determines management of these patients augmented by fine needle biopsy. In UK, a non-diagnostic category for thyroid cysts (Thy1c) exists, whereas the Bethesda system combines ‘non-diagnostic—cyst fluid only’ into Category I along with paucicellular and acellular results. The aim was to assess the ability of Thy1c cytology to exclude malignancy.

Methods

We undertook a retrospective study of patients undergoing thyroidectomy with Thy1c cytology from analysis of the Unit database. Additionally, we made a retrospective search in our pathology database for reports combining ‘papillary thyroid carcinoma’ with ‘cyst’ or ‘cystic’ and compared histology with cytology.

Results

Between 2003 and 2023 115 patients (97 women, median age 44y, range 16–72) underwent thyroidectomy following Thy1c cytology. Indications for surgery included recurrent cyst (90%); compressive symptoms (9%) and one thyrotoxicosis. In no patient was the primary diagnosis malignant; multinodular goitre was commonest (87.76%); benign cyst (19.16%); follicular adenoma (5.4%) and coincidental pT1a classical papillary thyroid carcinoma (PTC) (4.3%). In the retrospective audit, 61 pathology reports contained ‘PTC’ and ‘cyst’/‘cystic’. The cystic element was in primary tumour (31.51%); nodal metastasis (17.28%) and adjacent benign disease (13.21%). Only 5 (8%) patients had Thy1c cytology; 4 had pT1a tumours and one a benign cyst and a 19 mm PTC.

Conclusion

Thy1c category reliably excludes significant malignancy. For patients with symptomatic cysts, ultrasound assessment and Thy1c cytology can guide the clinician to treat with either ablation or resection without the fear of mistreating a thyroid cancer.

Graphical Abstract

This retrospective study demonstrates that a Thy1c cytology report following cyst aspiration is reliable in excluding clinically significant thyroid cancer prior to definitive treatment of the cyst.

Conflicts of Interest

The authors declare no conflicts of interest.

Open Research

Data Availability Statement

The data that support the findings of this study are available on request from the corresponding author. The data are not publicly available due to privacy or ethical restrictions.

References

1O. H. Clark, Q.-Y. Duh, E. Kebebew, J. E. Gosnell, and W. T. Shen, Textbook of Endocrine Surgery (San Francisco: JP Medical Ltd, 2016).
10.5005/jp/books/12798
Google Scholar
2K. G. Burnand, The New Aird's Companion in Surgical Studies (London, UK: Churchill Livingstone, 2005).
Google Scholar
3G. Russ, S. J. Bonnema, M. F. Erdogan, C. Durante, R. Ngu, and L. Leenhardt, “European Thyroid Association Guidelines for Ultrasound Malignancy Risk Stratification of Thyroid Nodules in Adults: The EU-TIRADS,” European Thyroid Journal 6 (2017): 225–237.
10.1159/000478927
PubMed Web of Science® Google Scholar
4K. N. Patel, L. Yip, C. C. Lubitz, et al., “The American Association of Endocrine Surgeons Guidelines for the Definitive Surgical Management of Thyroid Disease in Adults,” Annals of Surgery 271 (2020): e21–e93.
10.1097/SLA.0000000000003580
PubMed Web of Science® Google Scholar
5M. C. Frates, C. B. Benson, J. W. Charboneau, et al., “Management of Thyroid Nodules Detected at US: Society of Radiologists in Ultrasound Consensus Conference Statement,” Ultrasound Quarterly 22 (2006): 231–238.
10.1097/01.ruq.0000226877.19937.a1
PubMed Google Scholar
6J. J. Cronan, “Thyroid Nodules: Is It Time to Turn off the US Machines?,” Radiology 247 (2008): 602–604.
10.1148/radiol.2473072233
PubMed Web of Science® Google Scholar
7C. Lobo, A. McQueen, T. Beale, and G. Kocjan, “The UK Royal College of Pathologists Thyroid Fine-Needle Aspiration Diagnostic Classification Is a Robust Tool for the Clinical Management of Abnormal Thyroid Nodules,” Acta Cytologica 55 (2011): 499–506.
10.1159/000333234
PubMed Web of Science® Google Scholar
8L. Torregrossa, A. M. Poma, E. Macerola, et al., “The Italian Consensus for the Classification and Reporting of Thyroid Cytology: Cytohistologic and Molecular Correlations on 37,371 Nodules From a Single Institution,” Cancer Cytopathology 130 (2022): 899–912.
10.1002/cncy.22618
CAS PubMed Web of Science® Google Scholar
9S. Z. Ali and E. S. Cibas, The Bethesda System for Reporting Thyroid Cytopathology: Definitions, Criteria and Explanatory Notes (Cham, Switzerland: Springer Science & Business Media, 2010).
10.1007/978-0-387-87666-5
Google Scholar
10D. N. Poller, V. Doyle, P. Trimboli, and M. Bongiovanni, “Rates of Thy 1-Non-diagnostic Thyroid Fine Needle Aspiration Using the UK Royal College of Pathologists Thy Terminology. A Systematic Review of the Literature Comparing Patients Who Undergo Rapid On-Site Evaluation and Those Who Do Not,” Cytopathology 31 (2020): 502–508.
10.1111/cyt.12804
PubMed Web of Science® Google Scholar
11W. M. Tunbridge, D. C. Evered, R. Hall, et al., “The Spectrum of Thyroid Disease in a Community: The Whickham Survey,” Clinical Endocrinology 7 (1977): 481–493.
10.1111/j.1365-2265.1977.tb01340.x
CAS PubMed Web of Science® Google Scholar
12P. Perros, K. Boelaert, S. Colley, et al., “Guidelines for the Management of Thyroid Cancer,” Clinical Endocrinology 81, no. Suppl 1 (2014): 1–122.
10.1111/cen.12515
CAS PubMed Web of Science® Google Scholar
13D. Parkinson, S. Aziz, R. Bentley, and S. J. Johnson, “Thyroid Cytology-Histology Correlation Using the RCPath Terminology for Thyroid Cytology Reporting,” Journal of Clinical Pathology 70 (2017): 648–655.
10.1136/jclinpath-2016-204022
CAS PubMed Web of Science® Google Scholar
14F. Nardi, F. Basolo, A. Crescenzi, et al., “Italian Consensus for the Classification and Reporting of Thyroid Cytology,” Journal of Endocrinological Investigation 37 (2014): 593–599.
10.1007/s40618-014-0062-0
PubMed Web of Science® Google Scholar
15A. K. Abou-Foul, J. Muzaffar, E. Diakos, J. E. Best, N. Momtahan, and S. Jayaram, “Correlation Between Thyroid Fine Needle Aspiration Cytology and Postoperative Histology: A 10-Year Single-Centre Experience,” Cureus 13 (2021): e14504.
PubMed Google Scholar
16A. Rovira, I. J. Nixon, and R. Simo, “Papillary Microcarcinoma of the Thyroid Gland: Current Controversies and Management,” Current Opinion in Otolaryngology & Head and Neck Surgery 27 (2019): 110–116.
10.1097/MOO.0000000000000520
PubMed Web of Science® Google Scholar
17A. E. Espinosa De Ycaza, K. M. Lowe, D. S. Dean, et al., “Risk of Malignancy in Thyroid Nodules With Non-Diagnostic Fine-Needle Aspiration: A Retrospective Cohort Study,” Thyroid 26 (2016): 1598–1604.
10.1089/thy.2016.0096
PubMed Web of Science® Google Scholar
18G. Güney and İ. T. Şahiner, “Malignancy Rates of Thyroid Cytology: Cyst Fluid Benign or Non-Diagnostic?,” Medical Science Monitor 23 (2017): 3556–3561.
10.12659/MSM.905718
PubMed Web of Science® Google Scholar
19R. Kanematsu, M. Hirokawa, M. Higuchi, et al., “Risk of Malignancy and Clinical Outcomes of Cyst Fluid Only Nodules in the Thyroid Based on Ultrasound and Aspiration Cytology,” Diagnostic Cytopathology 48 (2020): 30–34.
10.1002/dc.24323
PubMed Web of Science® Google Scholar
20A. Gupta, S. Ly, L. A. Castroneves, et al., “A Standardized Assessment of Thyroid Nodules in Children Confirms Higher Cancer Prevalence Than in Adults,” Journal of Clinical Endocrinology and Metabolism 98 (2013): 3238–3245.
10.1210/jc.2013-1796
CAS PubMed Web of Science® Google Scholar

Volume36, Issue3

May 2025

Pages 236-239