thyroid | Acta Medica Marisiensis

High-risk morphological features are less prevalent among small (<5mm) papillary thyroid microcarcinomas compared to larger (≥5mm) tumors: a study of 206 cases

Emőke – Andrea Szász¹, Adela Nechifor-Boilă^1,2, Ancuța Zahan¹, Angela Borda^1,3

1. Department of Histology, George Emil Palade University of Medicine, Pharmacy, Science, and Technology of Targu Mures, Romania
2. Department of Pathology, Targu Mures County Hospital, Targu Mures, Romania
3. Department of Pathology, Targu Mures Emergency County Hospital, Targu Mures, Romania

DOI: 10.2478/amma-2021-0016

Introduction: Papillary thyroid microcarcinoma (PTMC) is defined as a PTC measuring 1 cm or less, incidentally discovered. The aim of this study was to determine whether small (<5mm) tumors by contrast with large (≥5mm) ones are less frequently associated with high-risk morphological features, predictive of tumor aggressiveness.
Materials and methods: All consecutive PTMC cases registered at the Department of Pathology, Târgu-Mureş Emergency County Hospital between 2003-2014 were reviewed. The following have been assessed: tumor size, subcapsular versus nonsubcapsular location, extrathyroidal extension/invasion into the perithyroidal adipose tissue, multifocality, resection margins, lymph node involvement, histological variant, tumor border, stromal reaction (fibrosis/desmoplasia/sclerosis), presence of plump pink cells, nuclear features of the tumor cells, intratumoral lymphocytic infiltrate, multinucleated giant cells, psammoma bodies and stromal calcification. The cases were split in two categories: small (< 5mm) and large (≥ 5mm) PTMCs and the pathological features were evaluated in comparison.
Results: Our study included 206 cases, 91 large and 115 small PTMCs, respectively. Large PTMCs were signiﬁcantly associated with the presence of plump pink cells (p=0.002), well developed PTC nuclear features (p=0.003), stromal reaction (ﬁbrosis/desmoplasia/sclerosis) (p<0.001), infiltrative tumor border (p=0.011), subcapsular location (p<0.001), positive resection margins (p=0.022), stromal calcifications (p<0.001) and intratumoral multinucleated giant cells (p<0.001). Small PTMCs were generally well circumscribed and nonsubcapsular.
Conclusions: Our results have shown that small (<5mm) PTMCs are less frequently associated with high-risk morphological features, predictive of tumor aggressiveness compared with large (≥5mm) tumors and could thus be considered as low-risk cancers.

Distinct Morphological Features Predictive for Aggressiveness of Papillary Thyroid Microcarcinoma: a Study of 72 Cases and 80 Tumor Foci

Nechifor-Boilă Adela^1,2, Zahan Ancuţa Elena^1,3*, Căpraru Oana³, Cătană Ramona³, Fişus Andreea², Berger Nicole⁴

1 Departament of Histology, University of Medicine and Pharmacy of TirguMures, Romania
2 Department of Pathology, University of Medicine and Pharmacy of TirguMures, Romania
3 Departament of Endocrinology, University of Medicine and Pharmacy of TirguMures, Romania
4 Department of Pathology, Centre Hospitalier Lyon Sud, Hospices Civils de Lyon, France

DOI: 10.1515/amma-2015-0112

Introduction: In this study, we aimed to investigate the importance of some distinctive morphological parameters in predicting the extrathyroidal extension, as marker of aggressiveness, in a series of papillary thyroid microcarcinoma (PTMC) cases.
Material and methods: All consecutive PTMC cases, sized ≥5mm, registered at the Department of Pathology, Tîrgu-Mureş Emergency County Hospital from January 2002 to December 2013 were re-evaluated. The following histological features were noted: the multifocality, the extrathyroidal extension, the histologic variant, the tumor’s border (well circumscribed versus infiltrative), the PTC nuclear features (well developed versus subtle), the tumor associated stromal reaction (fibrosis/desmoplasia/sclerosis versus none of these changes), the presence of “plump pink” cells, psammoma bodies, intratumoral lymphocytic infiltrate, cystic change, back-to-back arrangement, intratumoral multinucleated giant cells and lymph node involvement.
Results: Our study included 72 PTMC cases, summing up to a total of 80 PTMC foci. We have shown that extrathyroidal extension is significantly associated with the presence of “plump pink”cells (p=0.0019), well developed nuclear features of PTC (p=0.018) and tumor associated stromal reaction (fibrosis/dezmoplazia/sclerosis) (p<0.0001). Other parameters were more prevalent among PTMC foci with extrathyroidal extension, but did not reach statistical significance.
Conclusion: Our results pointed out the importance of a distinct set of morphological microscopical parameters, predictive for extrathyroidal extension in PTMC cases (“plump pink” cells, well developed PTC nuclear features, tumor associated stromal reaction, infiltrative tumor borders and conventional PTC histology). All these parameters are important to be mentioned in the histopathological reports, as they might be associated with a more aggressive biological behaviour.