Multifocal Fibrosing Thyroiditis: A High-Volume Center Experience

Introduction: Multifocal fibrosing thyroiditis (MFT) is a rare and underrecognized fibroinflammatory lesion of the thyroid characterized by multiple discrete fibrotic foci with reactive epithelial changes. Its morphologic overlap with papillary thyroid carcinoma (PTC) and its reported coexistence with PTC have generated ongoing debate regarding its clinical and biological significance. The primary aim of this study is to characterize the clinicopathologic features of MFT across a large single-center experience.Methods: A retrospective case series was conducted at a single endocrine center between October 2022 and January 2026.

All patients with histopathologically confirmed MFT were included. Demographic, clinical, laboratory, radiologic, surgical, and histopathologic data were collected and analyzed descriptively.Results: Twenty-seven patients were identified, with a mean age of 45.1±8 years, of whom 22 (81.5%) were female. Twenty-four patients underwent total thyroidectomy (88.9%).

Concurrent PTC was identified in 11 cases (40.7%). Among the 11 PTC cases, 8 (72.7%) were unifocal, and 3 (27.3%) were multifocal.Conclusion: Multifocal fibrosing thyroiditis is a rare thyroid lesion with distinctive histopathologic features. Greater awareness of this entity may improve diagnostic accuracy and clarify its clinical significance.