We describe the case of a 48-year-old woman who presented with a thyroid lesion incidentally detected on positron emission tomography/computed tomography for a suspicious lung lesion. Subsequent clinical examination and investigations revealed a 3 cm nodule in the left lower pole of the thyroid. Fine needle aspiration was indeterminate for malignancy. A left hemithyroidectomy was performed and histology confirmed a benign thyroid adenoma with an incidental micropapillary carcinoma. The literature regarding the best management for thyroid incidentalomas remains uncertain and, as such, each patient must be managed on an individual basis.