ABSTRACT
Summary: A 59-year-old male presented with an accidental thyroid mass in 2022. Ultrasound and CT scan showed a nodule 5.2 × 4.9 × 2.8 cm (EU-TIRADS 4) in the right lobe of the thyroid gland. Taking into account the results of the fine needle aspiration biopsy (Bethesda V), intrathyroid localization, and absence of clinical symptoms, a malignant tumor of the thyroid gland was suspected. The patient underwent total thyroidectomy using fluorescence angiography with indocyanine green, and two pairs of intact parathyroid glands were visualized in typical localization. Unexpected histological and immunohistochemistry examinations revealed parathyroid carcinoma. Due to the asymptomatic course of the disease and atypical localization of parathyroid tumor, primary hyperparathyroidism was not suspected before the surgery. The diagnosis of asymptomatic intrathyroid parathyroid cancer is a serious diagnostic challenge for a wide range of specialists. Learning points: Parathyroid cancer is a rare disease that may be asymptomatic. Intrathyroidal localization of parathyroid carcinoma is casuistic and challenging for diagnosis, and the treatment strategy is not well defined. Preoperative parathyroid hormone and serum calcium testing are recommended for patients with solid thyroid nodules (Bethesda IV-V).
ABSTRACT
DNA repair can prevent mutations and cancer development, but it can also restore damaged tumor cells after chemo and radiation therapy. We performed RNA sequencing on 95 human pathological thyroid biosamples including 17 follicular adenomas, 23 follicular cancers, 3 medullar cancers, 51 papillary cancers and 1 poorly differentiated cancer. The gene expression profiles are annotated here with the clinical and histological diagnoses and, for papillary cancers, with BRAF gene V600E mutation status. DNA repair molecular pathway analysis showed strongly upregulated pathway activation levels for most of the differential pathways in the papillary cancer and moderately upregulated pattern in the follicular cancer, when compared to the follicular adenomas. This was observed for the BRCA1, ATM, p53, excision repair, and mismatch repair pathways. This finding was validated using independent thyroid tumor expression dataset PRJEB11591. We also analyzed gene expression patterns linked with the radioiodine resistant thyroid tumors (n = 13) and identified 871 differential genes that according to Gene Ontology analysis formed two functional groups: (i) response to topologically incorrect protein and (ii) aldo-keto reductase (NADP) activity. We also found RNA sequencing reads for two hybrid transcripts: one in-frame fusion for well-known NCOA4-RET translocation, and another frameshift fusion of ALK oncogene with a new partner ARHGAP12. The latter could probably support increased expression of truncated ALK downstream from 4th exon out of 28. Both fusions were found in papillary thyroid cancers of follicular histologic subtype with node metastases, one of them (NCOA4-RET) for the radioactive iodine resistant tumor. The differences in DNA repair activation patterns may help to improve therapy of different thyroid cancer types under investigation and the data communicated may serve for finding additional markers of radioiodine resistance.
