Clinical presentation: A 48-year-old man who was operated 6 years earlier because of medullary cancer. He was irradiated after surgery.

Palpation: a hard nodule with uneven surface in the left lobe and in the jugular area.

Functional state: euthyroidism on daily 137.5 microgram levothyroxine.

Ultrasonography. The entire left lobe was composed of multiple hypoechogenic nodules with irregular borders. They contained coarse and microcalcifications, too. A similar lesion was in the jugular area. Multiple metastatic lymph nodes were present in the left side of the neck.

Cytology resulted in medullary cancer.

Serum calcitonin level was 477 pg/mL (normal value: 2-10).

Histopathology disclosed medullary carcinoma.

Comment. It is worth analyzing the azurophilic cytoplasmic granulations which is a very specific cytological sign of a medullary carcinoma. The cellular arrangement is also noteworthy: 4-6 cells form small groups resembling a microfollicle. The lack of polarity seen in a microfollicle is the important finding.