Clinical data: A 74-year-old woman was referred for evaluation of a lymph node in the right side of the neck. The node was detected on PET-CT scan. She was operated on ductal invasive breast cancer 30 years ago. Twenty-five years later, a recurrent metastatic lymph node in the right axilla was removed. She was now investigated because of 7 kg lost in weight. There was no other PET-positive finding.

Palpation: a firm node lateral and lower to the right thyroid.

Functional state: subclinical hypothyroidism (TSH 7.60, FT4 15.2 pM/L, aTPO 19 U/mL).

Ultrasonography: the right thyroid was echonormal while the left lobe contained moderately hypoechogenic areas with a 50% echogenicity index. There was a hypoechogenic mass lower and lateral to the right thyroid. The lesion did not present a regular hilum.

Cytology was performed from the mass in the right side of the neck and resulted in carcinoma corresponding to metastasis of a ductal breast cancer.

Wash-out thyroglobulin level was 0.07 ng/mL, serum thyroglobulin was 9.04 ng/mL. Immunocytochemistry was performed and the tumor proved to be estrogen positive.

The node was removed, and histopathology disclosed a metastasis of a ductal breast carcinoma to a lymph node.

Comment. Although the recurrence of the breast cancer was very likely on the clinical and cytological data, a thyroidal origin could not be fully excluded. Note that the patient was disease free for 5 years and the only PET-positive finding was this lymph node far from the breast.