Abstract

Thyroid cancer is the most common endocrine malignancy, with differentiated thyroid carcinoma (DTC) accounting for approximately 90% of cases. DTC primarily includes papillary thyroid carcinoma (PTC), follicular thyroid carcinoma (FTC), and oncocytic thyroid carcinoma (OTC), each characterized by distinct histological and genetic profiles. Diagnostic strategies for DTC integrate advanced imaging modalities and cytopathological techniques. Cervical ultrasound is a cornerstone for evaluating suspicious thyroid nodules, complemented by systems like ACR-TIRADS for malignancy risk stratification. Fineneedle aspiration biopsy (FNAB) remains the gold standard, guided by the Bethesda System for Reporting Thyroid Cytopathology for risk-based management. DTC subtypes are defined by histopathological features. PTC, the most prevalent, exhibits hallmark nuclear changes and frequent lymphatic spread, driven by mutations such as BRAF p.V600E and RET fusions. FTC is characterized by hematogenous spread and key molecular drivers like RAS mutations and PAX8::PPARG fusions. OTC, a rare FTC variant, is less responsive to radioactive iodine (RAI) therapy due to limited iodine uptake. Staging systems such as the AJCC TNM and ATA risk stratification provide frameworks for prognosis and treatment decisions. While the TNM system incorporates tumor size, nodal involvement, metastases, and patient age, the ATA system emphasizes recurrence risk. Prognosis varies, with PTC generally showing excellent survival rates, whereas aggressive variants, widely invasive FTC, and OTC have poorer outcomes. Surgical management remains a cornerstone of treatment, ranging from lobectomy to total thyroidectomy with lymph node dissection. RAI therapy and long-term monitoring are integral to optimizing outcomes and mitigating recurrence. Molecular diagnostics, including genomic profiling, further refine risk stratification and personalized treatment strategies for DTC.

Keywords

differentiated thyroid carcinoma, papillary thyroid carcinoma thyroid cancer staging, fine-needle aspiration biopsy, radioactive iodine therapy