Riedel thyroiditis secondary to papillary thyroid carcinoma: A case report

Area of Science:

• Endocrinology
• Pathology
• Oncology

Background:

• Riedel thyroiditis (RT) is a rare manifestation of immunoglobulin G4-related disease (IgG4-RD).
• IgG4-RDs are associated with an increased risk of malignancy.
• Malignancy-induced IgG4-RDs are exceptionally rare, with limited documentation in medical literature.

Purpose of the Study:

• To report the first documented case of Riedel thyroiditis secondary to papillary thyroid carcinoma.
• To elucidate the relationship between malignant tumors and IgG4-RDs.
• To emphasize the diagnostic challenges and clinical implications of this rare association.

Main Methods:

• A 47-year-old male presented with a neck nodule.
• Diagnostic workup included histopathological examination revealing features consistent with RT.
• The patient underwent surgical intervention (thyroidectomy and neck lymph node dissection).

Main Results:

• The patient was diagnosed with RT secondary to papillary thyroid carcinoma.
• Histopathology confirmed fibrous tissue hyperplasia, atrophic thyroid follicles, and inflammatory cell infiltration.
• The patient recovered well post-surgery and is on levothyroxine therapy.

Conclusions:

• Riedel thyroiditis can present with imaging features mimicking thyroid malignancy.
• High index of suspicion and integrated clinicopathologic assessment are crucial for accurate diagnosis.
• Distinguishing RT from malignancy is vital to prevent overtreatment and unnecessary surgical procedures.