Work

Diagnostic limitations and procedure-related implantation in follicular-patterned thyroid tumors: a focused review with two illustrative cases

Year: 2026

Type: article

Abstract: The rapid adoption of thyroid radiofrequency ablation (RFA) and remote-access thyroid surgery has changed the therapeutic landscape for thyroid nodules. These approaches can reduce visible scarring, shorten recovery, and offer alternatives to conventional surgery in appropriately selected patients. However, their expansion has also exposed a persistent diagnostic vulnerability: follicular-patterned thyroid tumors cannot be definitively classified as benign or malignant by cytology alone, because the diagnosis of follicular thyroid carcinoma requires histologic assessment of capsular and/or vascular invasion. This review first summarizes the current clinical context of minimally invasive thyroid intervention, the diagnostic boundaries of fine-needle aspiration and Bethesda reporting in follicular-lineage lesions, the definitions and published evidence for needle-tract or surgical-tunnel implantation, and the molecular context of DICER1-altered follicular-patterned tumors. Two implantation-related cases are used as illustrative clinical scenarios rather than as the primary evidentiary basis. The Discussion then addresses the major controversies, including procedural expansion, the role of benign cytology as a preprocedural gatekeeper, the uncertain role of molecular testing before ablation, terminology, patient selection, surveillance, research gaps, and potential developments. The available literature remains dominated by case reports and small series, and causal inference is limited. Nevertheless, repeated reports of tract- or tunnel-aligned deposits in follicular-lineage tumors suggest that implantation risk should be considered when selecting patients for ablative or remote-access interventions. Molecular alterations such as DICER1 RNase IIIb hotspot mutations may provide biological context, but they should not replace histologic classification. Future progress will require standardized reporting, prospective registries, molecularly annotated cohorts, and preprocedural algorithms that integrate imaging, cytology, molecular testing, procedural anatomy, and patient preference.

Source: Frontiers in Endocrinology

DOI: 10.3389/fendo.2026.1927184