Thirty-three percent were diagnosed with benign nodules (n=151), 36% with papillary or follicular thyroid cancer (n=168), 27% with Graves' disease (n=124), 3% with medullary thyroid cancer (n=14), and 1.5% underwent prophylactic thyroidectomy for MEN2a (n=7).
Histology was reviewed, and the patients were divided in the following three groups: poorly differentiated carcinoma [PDTC; group 1 (n = 27)]; papillary thyroid carcinoma with PDA [PTC with PDA; group 2 (n = 27)]; and follicular thyroid carcinoma with PDA [FTC with PDA; group 3 (n = 88)].
This was a retrospective cross-sectional evaluation of 115 archived samples, including: 47 benign (29 follicular adenoma, 11 diffuse hyperplasia, four thyroiditis, and three multinodular goiter), six follicular thyroid carcinomas (FTC), 24 follicular variant of papillary thyroid carcinomas (fvPTC), 27 classic variant of PTC (cPTC), eight diffuse sclerosing variant of PTC (dsvPTC), and three other PTC.
The prevalence of the fusions was determined by RT-PCR in 71 classical PTC, 45 follicular variants of PTC (FVPTC), 19 follicular thyroid adenomas (FTAs) and 22 follicular thyroid carcinomas (FTCs).
Skeletal muscle metastasis of papillary or follicular thyroid cancer (PTC/FTC) is a rare finding; only 11 cases of skeletal muscle PTC or FTC metastasis have been included in medical literature reviews.
The surgical resection specimen demonstrated FVPTC in 20 (74%) cases, classical type PTC in two (7%), solid variant of PTC in one (4%), and follicular thyroid carcinoma in four (15%).
Several single-nucleotide polymorphisms (SNPs) have been associated with papillary and follicular thyroid cancer (PTC and FTC, respectively) risk, but few have replicated.
For the sake of the discussion, well-differentiated carcinomas were divided into two main morphologic types: papillary carcinoma (classic and most variants) displaying BRAFV600E mutations and RET/papillary thyroid carcinoma rearrangements and the group of follicular patterned carcinomas that encompasses follicular carcinoma and the encapsulated form of follicular variant of papillary carcinoma, displaying RAS mutations and PAX8/PPARγ rearrangement.
We evaluated RETG691S (rs1799939), L769L (rs1800861), and S904S (rs1800863) polymorphisms to elucidate their possible role as risk factors in papillary thyroid cancer (PTC) and follicular thyroid cancer (FTC).
We have developed a home-brew tetracolor break-apart probe able to simultaneously identify the 2 most common genetic alterations in differentiated thyroid carcinoma: RET/PTC variants in papillary thyroid carcinoma and PAX8/PPARg fusion and variants in follicular thyroid carcinoma.
German patients (n=253) with DTC (papillary thyroid carcinoma [PTC] and follicular thyroid carcinoma [FTC]) and HC (n=302) were genotyped for polymorphisms within the vitamin D metabolizing enzymes such as 25-hydroxylase (CYP2R1[rs12794714, rs10741657]), 25-hydroxyvitamin D-1α-hydroxylase (CYP27B1[rs10877012, rs4646536]), and 25-hydroxyvitamin D 24-hydrolase (CYP24A1[rs927650, rs2248137, rs2296241]).
As PAX8/PPARG and RET/PTC rearrangements have been detected in follicular thyroid carcinomas (FTCs) and papillary thyroid carcinomas (PTCs), their detection in FNA smears could improve the FNA diagnosis.
Based on the four possible outcomes (FTA, C-PTC, FV-PTC, and FTC), about 80% of FTA and C-PTC and 50% of FV-PTC and FTC samples were correctly assigned.
Wild-type (nonrearranged) c-RET oncogene was overexpressed in 60% of PTC cases and absent in follicular thyroid carcinoma (FTC), anaplastic thyroid carcinoma (ATC), follicular adenomas (FA) or normal thyroid.
We have analyzed RET rearrangements in post-Chernobyl papillary thyroid carcinomas (n = 29), follicular thyroid adenomas (n = 2), and follicular thyroid carcinoma (n = 1) by interphase fluorescence in situ hybridization (FISH) analysis on paraffin-embedded tissue sections.
In conclusion, chromosomal abnormalities are frequent in ATCs associated with FTC, but uncommon in those associated with PTC and in ATCs with no associated differentiated thyroid cancer.
The study found that the RET proto-oncogene is often stimulated in FCDT, not only in PTC but also in follicular tumors (FA and FTC), and may contribute to tumorigenesis of these tumors.
These identified chromosomal rearrangements activating RET and PPAR gamma 1 in a subset of papillary (PTCs) and follicular thyroid carcinomas (FTCs) and amplification of PKC epsilon in FTCs.
Whether a limited surgical approach is also justified in other cases, e.g. in any patient with intrathyroidal PTC or patients with micro-FTC (follicular thyroid carcinoma), remains to be shown and is the subject of ongoing investigations.
Our findings suggest that constitutive RET proto-oncogene activation may be involved in the development of mixed medullary-follicular thyroid carcinoma.
Several early events, including ras mutations in follicular thyroid carcinoma and RET gene rearrangement in papillary tumors, have been implicated in the neoplastic transformation of thyrocytes.