In April 2011, after positron emission tomography/computed tomography (CT/PET) to investigate a residual solid right lower lobe lung nodule following pneumonia, a 48-year-old woman was referred to a thyroid surgeon with an incidental thyroid lesion (Fig 1). She had a two-month history of throat discomfort but no voice dysfunction or difficulty breathing. Significant past medical history included right thyroid lobe surgery for a degenerative colloid adenoma 19 years previously. She had never had any thyroid hormone dysfunction and there was no family history of thyroid disease.  
On examination, she was clinically euthyroid. There was a visible 3cm nodule in the lower pole of the left lobe of the thyroid. There was no associated lymphadenopathy. Thyroid function tests were normal. Ultrasonography demonstrated a 3.75cm circumscribed, solid, echogenic nodule in the lower pole of the left lobe of the thyroid and radiological appearances suggested a follicular lesion. There was regrowth of the right thyroid remnant. Fine needle aspiration showed follicular cells that were graded as Thy3 (intermediate risk of malignancy).
After discussion with the patient about the alternative management options and in light of the undiagnosed lung lesion, she underwent an urgent left hemithyroidectomy and excision of the right thyroid remnant. There were no post-operative complications.
Pathology of the excised nodule revealed the index lesion was a benign thyroid adenoma. There was an incidental microcarcinoma measuring 0.8mm in the specimen. This was completely encapsulated and not adjacent to the thyroid capsule. The presenting lung lesion was ultimately determined to be unrelated to the thyroid lesion. Resection of the lung nodule revealed an area of necrotising granulomatous inflammation. There were no acid-fast bacilli or fungal bodies seen and there was no clear clinical indication of tuberculosis.