Fine-needle aspiration-induced infarction of a thyroid nodule: A rare diagnostic pitfall – A case report

Abstract

Fine-needle aspiration (FNA) is the most widely used diagnostic tool for evaluating thyroid nodules and plays a 
crucial role in guiding surgical management. Although considered safe and minimally invasive, it may rarely induce 
secondary histologic alterations, including nodule infarction, which can obscure histopathological interpretation 
and create diagnostic uncertainty. A 72-year-old woman presented with a gradually enlarging anterior neck swelling 
of 1 year’s duration. An earlier FNA had been reported as a colloid cyst. Repeat ultrasonography demonstrated a 
cystic lesion in the left thyroid lobe, and repeat FNA revealed atypia of undetermined significance, oncocytic type 
(Bethesda category III). Total thyroidectomy was performed 4 weeks after the repeat FNA because of indeterminate 
cytology and increasing lesion size. Histopathology demonstrated a completely infarcted thyroid nodule with no viable 
tumor cells. After multidisciplinary discussion, no further oncologic treatment was recommended, and the patient was 
started on thyroxine replacement therapy. Correlation of cytologic, clinical, and histopathological findings is essential 
for appropriate management.