Clinical presentation: A 37-year-old woman was referred for aspiration cytology of a nodule detected on evaluation of infertility.

Palpation: the right lobe was firmer than the left.

Functional state: euthyroidism (TSH 1.89 mIU/L).

Ultrasonography. The thyroid was echonormal. There was a hypoechogenic nodule in the central part of the left lobe. The lesion had irregular margins, presented microcalcifications and signs of both perinodular and intranodular blood flow.

Aspiration cytology resulted in papillary carcinoma.

Total thyroidectomy was performed, histopathology disclosed papillary carcinoma with a maximal diameter of 13 mm.

Comment. The malignant focus presents lobulated margins.