Thyroid Follicular Spectrum Lesions

Thyroid follicular spectrum lesions span a diagnostic continuum from benign adenomas and non-invasive follicular thyroid neoplasms with papillary-like nuclear features to invasive follicular carcinomas. Because fine-needle aspiration cytopathology cannot identify capsular or vascular invasion, definitive differentiation between benign and malignant follicular neoplasms remains impossible prior to surgical resection. Molecular profiling targeting RAS mutations, PAX8-PPARG fusions, and TERT promoter mutations refines pre-operative risk stratification. Reclassifying non-invasive encapsulated follicular variants as indolent lesions has successfully mitigated overtreatment, shifting modern surgical management from routine completion thyroidectomy toward conservative hemithyroidectomy.