Noninvasive Encapsulated Follicular Variant of Papillary Thyroid Cancer: Clinical Lessons from a Community-Based Endocrine Surgical Practice

Objective. Retrospective studies have found that noninvasive encapsulated follicular variant of papillary thyroid cancer (EFVPTC) exhibits highly indolent clinical behavior. We studied the clinical features of our patients with noninvasive EFVPTC tumors culled from a community endocrine surgical practice registry over the past four years. Methods. We interrogated the Memorial Center for Integrative Endocrine Surgery (MCIES) Registry for all recorded encapsulated follicular variant of papillary cancer pathologic diagnoses. We identified a subgroup of patients without capsular or vascular invasion and studied their clinical characteristics. Results. Thirty-seven patients met inclusion and exclusion criteria. The typical patient was young and female. Nodules averaged 3.1 cm in greatest dimension by ultrasound evaluation. Thirteen patients were found to have synchronous malignancies elsewhere in the thyroid (35%). At the time of this writing, we have not seen a clinical recurrence in any of our 37 noninvasive EFVPTC patients. Conclusions. Early clinical follow-up data suggests that the majority of noninvasive EFVPTC tumors exhibit indolent behavior, but clinical decision-making with regard to completion thyroidectomy, central lymph node dissection, and adjunctive radioiodine therapy often depends on the amount and type of synchronous thyroid cancer detected elsewhere in the thyroid gland and the central neck.