Riedel’s Thyroiditis – A Case Report with Histopathological Perspective

Riedel’s thyroiditis (RT) is a rare, chronic fibroinflammatory disease of the thyroid gland characterized by dense hyalinized fibrosis, often extending into adjacent soft tissues and mimicking invasive thyroid carcinoma. The etiology remains uncertain, although recent evidence suggests that it belongs to the spectrum of IgG4-related systemic diseases. We present a case of a 41-year-old female with a progressively enlarging neck mass and compressive symptoms, ultimately diagnosed as RT on histopathology. This case highlights the diagnostic challenge and the indispensable role of histopathology in distinguishing RT from mimicking conditions like thyroid malignancy.