Two cases of bacterial suppurative thyroiditis caused by Streptococcus anginosus.

Acute suppurative thyroiditis (AST) is a rare clinical condition. Streptococcus anginosus has a propensity of producing empyema in the head and neck. Here, we reported two cases of AST caused by S. anginosus. A 44-year-old man presented with anterior neck tender swelling and odynophagia for 12 days. He had thyrotoxicosis. He was initially diagnosed as thyroid cancer due to the misleading computed tomography report. Fine needle aspiration (FNA) yielded pus and neutrophils. S. anginosus was isolated from pus. After aspiration of abscess and treatment with sensitive antibiotics, he recovered uneventfully with 3 weeks treatment. He was euthyroid 3 months later. The other case is a 40-year-old women complained of fever and left neck swelling for 20 days. Magnetic resonance imaging showed left neck inflammatory changes. FNA revealed pus and inflammatory cells infiltration. She had moderately decreased level of thyroid-stimulating hormone (TSH). Blood cultures were positive for S. anginosus. After penicillin treatment, TSH level returned to normal range, and the nodule gradually resolved. She recovered uneventfully after 5 weeks treatment. S. anginosus has a previously unappreciated clinical niche in AST. Once AST is clinically concerned, FNA procedure should be performed as early as possible.