Coincident Suppurative Thyroiditis and Graves Disease in a Patient with Infected Branchial Cleft CYST

ABSTRACT Objective Acute suppurative thyroiditis (AST) is frequently caused by anatomic abnormalities, including branchial cleft cysts. Patients with AST are typically euthyroid, but thyrotoxicosis may occur. Thyroid antibodies are usually not present in AST. Our objective is to describe a teenage male who presented with concomitant suppurative thyroiditis and Graves disease (GD). Methods We report a case of an infected left branchial cleft cyst with AST and concurrent GD in an adolescent male. Thyroid function tests and thyroid imaging were used for diagnostic evaluation, and the patient was managed with antibiotics, analgesia, and surgery. Results A 17-year-old male with a history of an infected left fourth branchial cleft cyst presented with recurrence of neck pain, odynophagia, and fever. Serum labs showed thyrotoxicosis and elevated thyroid antibodies and inflammatory markers. Magnetic resonance imaging showed an abscess adjacent to the left thyroid lobe. Symptoms resolved after antibiotic therapy, but laboratory tests showed persistent subclinical thyrotoxicosis. Four months later, he underwent excision of the branchial cleft cyst and left thyroid lobe. Two months after surgery, evaluation showed overt thyrotoxicosis with laboratory tests confirming GD. Methimazole was initiated and thyroid function subsequently normalized. Conclusion This patient manifested a rare coincidence of AST due to a branchial cleft cyst and autoimmune thyroid disease. Further studies are needed to determine if there is any relationship between AST and development of thyroid autoimmunity. Assessment of thyroid autoimmunity may be considered in patients with prior or recurrent AST.