Endocrine Abstracts (2017) 49 EP1414 | DOI: 10.1530/endoabs.49.EP1414

Significant difference between the prevalence of C cell hyperplasia (CCH) in benign thyroid nodules without histological thyroiditis (HT) and in papillary/follicular thyroid cancers (PTC/FTC) at histology

Letizia Pieruzzi1, Eleonora Molinaro1, Laura Agate1, Valeria Bottici1, Liborio Torregrossa2, Clara Ugolini2, Fulvio Basolo2, Paolo Vitti1 & Rossella Elisei1

1Medical Area and Experimental Medicine Department, Endocrinology section, University of Pisa, Pisa, Italy; 2Department of Oncology Section of Cytopathology, Pathology, University of Pisa, Pisa, Italy.

Background: CCH and serum hypercalcitoninemia (iperCT) can be found in benign thyroid diseases such as thyroiditis and in some cases of papillary (PTC) or follicular (FTC) thyroid microcarcinomas. The question of whether the association with these latter is related to the malignancy of the nodule is still unclear.

Aim of the study: To evaluate the difference in the CCH prevalence, at histology, in a series of benign (BTN) and malignant (PTC/FTC) thyroid nodules. The correlation with the serum CT was also analysed.

Materials and methods: We selected 315 consecutive cases surgically treated between 2012 and 2016 in our Hospital: 137/315(43.5%) resulted to be BTN and 178/315(56.5%) to be PTC/FTC. In 27/315(8.5%) cases there was a serum iperCT (Immulite 2000, Siemens). The definition of CCH was based on the presence of more than 50 C-cells at least in one microscope field, in a thyroid cross section.

Results: At a first analysis no differences were observed in the prevalence of CCH between BTN and PTC/FTC. When we excluded from the analysis the cases with reported HT, both benign and malignant, the prevalence of CCH was statistically significant more frequent and bilateral in PTC/FTC (32.6%) than in BTN (19.5%)(P<0.05). The cases with iperCT were exclusively in the PTC/FTC group and among them those case with iperCT showed the highest prevalence of CCH (P<0.001). In PTC/FTC with serum iperCT we observed that 11/21(52.4%) were follicular variant PTC(FVPTC) while this variant was present in only 30/84(35.7%) PTC/FTC without iperCT (P<0.05). The cases with iperCT were also more often multifocal (P<0.005).

Conclusions: CCH is more frequent in PTC/FTC than in BTN when the cases with HT were excluded; the serum iperCT was found exclusively in the PTC/FTC group and these cases showed the highest prevalence of CCH; a higher prevalence of FVPTC and multifocal cases were observed in the PTC/FTC group associated with CCH.