Clinical history: A 57 year-old male presented with pressure on the anterior neck, bilateral thyroid enlargement, hypothyroidism
What is your diagnosis?
Discussion and answer
Diagnosis: Riedel's disease
Histologic features: Parenchyma is replaced by dense collagenous tissue with loose lymphoplasmacytic infiltrate and remnants of thyroid follicles with oncoytic metaplastic changes. Note the broad bands of fibrosis with keloid-like glassy fibers.
Riedel's thyroiditis, also called Riedel's struma, fibrous thyroiditis, is a densely fibrotic inflammatory process involving thyroid gland and adjacent neck . It can be associated with inflammatory fibrosclerosis / multifocal systemic fibrosclerosis (mediastinal or retroperitoneal fibrosis, sclerosing cholangitis, inflammatory pseudotumor of orbit).