Secondary infection and ischemic necrosis after fine needle aspiration for a painful papillary thyroid carcinoma: a case report

BACKGROUND: Papillary thyroid carcinoma (PTC) is often asymptomatic and rarely presents as a painful goiter. Further, the thyroid gland is not easily infected. Therefore, acute suppurative thyroiditis (AST) is unusual. PTC is also seldom combined with AST. We report a case of painful PTC with secondary infection after fine needle aspiration (FNA). CASE: A 19-year-old girl complained of a painful goiter without skin change after an episode of upper airway infection. PTC was diagnosed according to the FNA cytology (FNAC) at another hospital. The goiter became more painful after FNA. The patient's second FNAC at our hospital revealed only many polymorphonuclear leukocytes (PMNs). Antibiotic treatment ameliorated the pain, but the goiter persisted. The third FNAC revealed some PMNs and papillary carcinomatous cells. After total thyroidectomy, pathology revealed ischemic necrosis with a focal PMN aggregation around the needle track and papillary carcinomatous cells nearby. According to the time sequence, secondary infection after FNA was suspected. CONCLUSION: A painful goiter is an unusual presentation of PTC. Although FNAC is feasible for studying a thyroid lesion, malignant cells might be missed when secoandary injection and ischemic necrosis occur after FNA. Therefore, aseptic procedures are necessary to prevent bacteria from seeding into the thyroid.