Polymorphisms in long non-coding RNA and microRNA genes may play a significant role in the susceptibility and progression of papillary thyroid carcinoma (PTC). The current study investigates the polymorphisms HOTAIR rs920778, MIR155HG rs1893650, TERC rs10936599, miR-155 rs767649, miR-196a2 rs11614913 and miR-146a rs2910164 in 102 PTC patients and 106 age- and sex-matched controls of the Caucasian Serbian population, using real-time PCR. We observed differences in genotype distributions of the HOTAIR rs920778 (p = 0.016) and MIR155HG rs1893650 (p = 0.0002) polymorphisms between PTC patients and controls. HOTAIR rs920778 was associated with increased PTC susceptibility (adjusted OR = 1.497, p = 0.021), with the TT variant genotype increasing the risk compared to the CC genotype (OR = 2.466, p = 0.012) and C allele carriers (CC + CT) (OR = 1.585, p = 0.006). The HOTAIR rs920778 TT genotype was associated with lymph node metastasis (p = 0.022), tumor recurrence (p = 0.016), and progression-free survival (p = 0.010) compared to C allele carriers. Multivariate Cox regression revealed that ATA risk (HR = 14.210, p = 0.000004) and HOTAIR rs920778 (HR = 2.811, p = 0.010) emerged as independent prognostic factors in PTC. A novel polymorphism, MIR155HG rs1893650, was negatively correlated with susceptibility to PTC, with TC heterozygotes exerting a protective effect (OR = 0.268, p = 0.0001). These results suggest that the polymorphisms HOTAIR rs920778 and MIR155HG rs1893650 could be potential prognostic and risk biomarkers in papillary thyroid carcinomas.

Background: Small papillary thyroid carcinomas with the largest dimension of 10 mm are slow-growing and self-limiting tumors, most of which have no potential for progression, rarely becoming clinically evident carcinomas or undergoing regressive changes. Their anaplastic transformation, primarily in the thyroid gland or into lymph node metastasis, is extremely rare. Case Presentation: A 66-year-old female patient was admitted to our hospital for diagnostics and treatment of a large tumor on the left neck side. Preoperative imaging and cytological findings of the neck tumor suggested metastasis of papillary thyroid carcinoma. Total thyroidectomy and metastasectomy were performed. In the final diagnosis, anaplastic transformation of the papillary thyroid carcinoma’s metastasis in the neck was confirmed. Opposite to advanced dedifferentiation of metastasis, primary tumor foci in the thyroid were regressed and replaced with sclerosis and microcalcification. The synchronous co-occurrence of incidental primary thyroid carcinoma and anaplastic thyroid carcinoma originating from ectopic cervical thyroid tissue was considered diagnostically. Conclusions: The case highlights the necessity of regular monitoring of the thyroid and neck lymph nodes for patients under active surveillance, including those with small calcified tumor foci. This paper also comprehensively reviews the existing literature on this topic.

Thyroid-like follicular carcinoma of the kidney (TLFC-K) is a rare primary kidney carcinoma with fewer than 60 reported cases. Current data suggest that TLFC-K has low malignant potential, with only a few reported cases of unfavorable clinical behavior. Histologically, TLFC-K is indistinguishable from kidney metastasis of well-differentiated follicular cell-derived thyroid carcinomas. Furthermore, folliculo-tubular patterns can be seen in different types of kidney lesions, making assessing follicular architecture in the kidney diagnostically challenging. We present a case of TLFC-K with a list of differential diagnoses. A hyperechoic tumor was found incidentally in the upper pole of the right kidney of a 66-year-old man. The patient underwent a radical nephrectomy. Histologically, the tumor was well-circumscribed, composed of follicular/tubular structures of different sizes filled with colloid-like material. Immunohistochemically, the absence of a positive reaction for thyroglobulin and TTF-1 excluded the secondary origin of the tumor from the thyroid. Tumor cells also showed diffuse positivity for vimentin and PAX8 and focal positivity for CK7 and CD10. The results of all other applied immunostaining tests did not align with those of different types of kidney tumors that may exhibit predominantly follicular patterns. Accordingly, TLFC-K was diagnosed. The patient shows no signs of disease relapse at the 5-month follow-up.