Background: Papillary thyroid microcarcinoma (PTMC) defines a group of papillary thyroid carcinomas, incidentally discovered, measuring 1 cm or less. The aim of our study was to evaluate the incidence and the pathological characteristics of PTMCs in our institution in the last 25 years, with special emphasis on the prognostic factors related to PTMCs. Material and methods: We performed a retrospective, cohort study on 255 PTMCs, registered in the Department of Pathology, Tîrgu-Mureş Emergency County Hospital between 1990 and 2014. Results: A significant increase in the incidence of PTMCs was observed in the 2004-2014 period, compared to 1990-2003 (7.6%, 229 PTMCs/3005 thyroid specimens vs. 1.2%, 23 PTMCs/1885 thyroid specimens). Conventional PTMCs accounted for most of PTMC cases (n=123 cases, 48.2%), followed by the follicular variant of PTC (n=117 cases, 45.9%). The increasing incidence of PTMCs was associated with a significant increase in the routine number of blocks sampled per case over the study period (R2 =0.72, p < 0.001). By means of the univariate and multivariate analysis, three risk factors were predictive for extrathyroidal extension in PTMCs: multifocality (Odds ratio [OR] 4.97, p-0.002), tumor size ≥ 5mm (OR 8.97, p-0.008) and lymph node involvement (OR 17.66 p<0.005). Conclusion: The incidence of PTMCs has revealed a significant increasing trend in our institution over the last 25 years. Multifocality, lymph node involvement and tumor size ≥ 5mm were found to be risk factors for extrathyroidal extension. These prognostic factors must be evaluated and clearly mentioned in the pathological report, to help a correct estimation of biological potential of the lesion and an appropriate postoperative management.
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1. DeLellis RA Lloyd RV Heitz PU Eng C. World Health Organization Classification of Tumours. Pathology and genetics of tumours of endocrine organs. Lyon: IARC Press. 2004;p.54-5.
2. YE. Nikiforov Paul W. Biddinger Lester D.R. Thompson. Diagnostic Pathology and Molecular Genetics of the Thyroid Second Edition- Chapter 7 - Thyroid Tumors: Classification Staging and General Considerations Chapter 11- Papillary Carcinoma Lippincott Williams & Wilkins. 2012;108-118183-243.
3. Kahn C Simonella L Sywak M et al. Postsurgical pathology reporting of thyroid cancer in New South Wales Australia. Thyroi. 2012;(22):604-10.
4. Davies L Welch HG. Current Thyroid Cancer Trends in the United States. JAMA Otolaryngol Head Neck Surg. 2014;140(4):317-322.
5. Kent WD Hall SF Isotalo PA et al. Increased incidence of differentiated thyroid carcinoma and detection of subclinical disease. CMAJ. 2007; (177):1357-61.
6. Hay ID Hutchinson ME Gonzalez-Losada T et al. Papillary thyroid microcarcinoma: a study of 900 cases observed in a 60-year period. Surgery. 2008;(144):980-8.
7. Hughes DT Haymart MR Miller BS et al. The most commonly occurring papillary thyroid cancer in the United States is now a microcarcinoma in a patient older than 45 years. Thyroid. 2011;(21):231-236.
8. Furio Pacini. Thyroid microcarcinoma. Best Practice & Research Clinical Endocrinology & Metabolism. 2012;421-429.
9. Grodski S Brown T Sidhu S et al. Increased incidence of thyroid cancer is due to increased pathologic detection. Surgery. 2008;(144):1038-43.
10. Udelsman R Zhang Y. The epidemic of thyroid cancer in the United States: The role of endocrinologists and ultrasounds. Thyroid. 2014;24(3):472-479.
11. Furio Pacini . Management of Papillary Thyroid Microcarcinoma: Primum Non Nocere! J Clin Endocrinol Metab. 2013;98(4):1391-1393.
12. Kitahara CM Platz EA Beane Freeman LE et al. Physical activity diabetes and thyroid cancer risk: A pooled analysis of five prospective studies. Cancer Causes & Control. 2012;23(3):463-71.
13. Howlander N Noone AM Krapcho M et al. J. SEER Cancer Statistics Review 1975-2008. National Cancer Institute; Bethesda MD: http://seer.cancer.gov/csr/1975_2008/ based on November 2010 SEER data submission posted to the SEER web site 2011.
14. Leenhardt L Grosclaude P Cherie-Challine L. Increased incidence of thyroid carcinoma in France: a true epidemic or thyroid nodule management effects? Report from the French Thyroid Cancer Committee. Thyroid. 2004;(14):1056-1060.
15. Roti E degli Uberti EC Bondanelli M et al. Thyroid papillary microcarcinoma: a descriptive and meta-analysis study. Eur J Endocrinol. 2008;(159):659-673.
16. Martinez-Tello FJ Martinez-Cabruja R Fernandez-Martin J et al. Occult carcinoma of the thyroid. A systematic autopsy study from Spain of two series performed with two different methods. Cancer. 1993;(71):4022-4029.
17. Harach HR Franssila KO Wasenius VM. Occult papillary carcinoma of the thyroid. A “normal” finding in Finland. A systematic autopsy study. Cancer 1985;(56):531-538.
18. Kovacs GL Gonda G Vadasz G et al. Epidemiology of thyroid microcarcinoma found in autopsy series conducted in areas of different iodine intake. Thyroid. 2005;(15):152-7.
19. Sakorafas GH Stafyla V Kolettis T et al. Microscopic papillary thyroid cancer as an incidental finding in patient treated surgically for presumably benign thyroid disease. Journal of Postgraduate Medicine. 2007;(53):23-26.
20. De Matos PS Ferreira AP Ward LS. Prevalence of papillary microcarcinoma of the thyroid in Brazilian autopsy and surgical series. Endocrine Pathology. 2006;(17):165-173.
21. Neuhold N Schultheis A Hermann M. Incidental papillary microcarcinoma of the thyroid-further evidence of a very low malignant potential: a retrospective clinicopathological study with up to 30 years of follow-up. Ann Surg Oncol. 2011;(18):3430.
22. Piana S Ragazzi M Tallini G et al. Papillary thyroid microcarcinoma with fatal outcome: evidence of tumor progression in lymph node metastases: report of 3 cases with morphological and molecular analysis. Hum Pathol. 2013;44(4):556-565.
23. Malandrino P Pellegriti G Attard M et al. Papillary thyroid microcarcinomas:a comparative study of the characteristics and risk factors at presentation in two cancer registries. JClin Endocrinol Metab. 2013;(98):1427-1434.
24. Besic N Pilko G Petric R et al. Papillary thyroid microcarcinoma: prognostic factors and treatment. J Surg Oncol. 2008;(97):221-5.
25. Yu XM Wan Y Sippel RS et al. Should all papillary thyroid microcarcinomas be aggressively treated? An analysis of 18445 cases. Ann Surg. 2011;(254):653-660.
26. Robenshtok E Grewal RK Fish S et al. A low postoperative nonstimulated serum thyroglobulin level does not exclude the presence of radioactive iodine avid metastatic foci in intermediate-risk differentiated thyroid cancer patients. Thyroid. 2013;23(4):436-442.
27. Moon HJ Kim EK Chung WY. Minimal extrathyroidal extension in patients with papillary thyroid microcarcinoma: is it a real prognostic factor? Ann Surg Oncol. 2011;(18):1916-23.
28. Zhang L Wei WJ Ji QH et al. Risk factors for neck nodal metastasis in papillary thyroid microcarcinoma: a study of 1066 patients. J Clin Endocrinol Metab. 2012;(97):1250-1257.
29. Kim BY Jung CH Kim JW et al. Impact of clinicopathologic factors on subclinical central lymph node metastasis in papillary thyroid microcarcinoma. Yonsei Med J. 2012;(53):924-930.
30. Zhao Q Ming J Liu C et al. Multifocality and total tumor diameter predict central neck lymph node metastases in papillary thyroid microcarcinoma. Ann Surg Oncol. 2013;(20):746-52.
31. Elisei R Viola D Torregrossa Let al. The BRAF (V600E) mutation is an independent poor prognostic factor for the outcome of patients with lowrisk intrathyroid papillary thyroid carcinoma: single institution results from a large cohort study. J Clin Endocrinol Metab. 2012;(97):4390-4398.
32. Virk RK Van Dyke AL Finkelstein A et al. BRAFV600E mutation in papillary thyroid microcarcinoma: a genotype-phenotype correlation. Mod Pathol. 2013;26(1):62-70.
33. Berger N Borda A. Pathologie thyroidienne parathyroidienne et surrenalienne- Techniques d`etude des lesions thyroidienne. Editura Sauramps Medical Montpellier. 2010;(366):29-33.
34. Nikiforov YE Biddinger PW Thompson LDR. Diagnostic Pathology and Molecular Genetics of the Thyroid Second Edition - Chapter 19 - Gross Examination Lippincott Williams & Wilkins. 2012;403-409.
35. Sobin LH Gospodarowicz MK Wittekind C. UICC TNM Classification of Malignant Tumours. 7th ed. Wiley-Liss; New York NY: 2009.
36. Friguglietti CU Dutenhefner SE Brandao LG et al. Classification of papillar thyroid microcarcinoma according to the size and fine-needle aspiration cytology: behavior and therapeutic implications. Head Neck. 2011;(33):696-701.
37. Buffet C Golmard JL Hoang C et al. Scoring system for predicting recurrences in patients with papillary thyroid microcarcinoma. Eur J Endocrinol. 2012;(167):267-275.
38. Ross DS Litofsky D Ain KB et al. Recurrence after treatment of micropapillary thyroid cancer. Thyroid. 2009;(19):1043-8.
39. Kim K Kim S Lee YS et al. Prognostic significance of tumor multifocality in papillary thyroid carcinoma and its relationship with primary tumor size: A retrospective study of 2309 consecutive patients. Annals of Surgical Oncology. 2015;22(1):125-31.
40. Ortiz Sebastian S Rodriguez Gonazles JM Parilla Paricio P et al. Papillary thyroid carcinoma: prognostic index for survival including the histological variety. Arch Surg. 2000;(135):272-277