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 thyroid and in the jugular area.

Functional state: euthyroidism on daily 137.5 microgram levo-tiroxine.

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.

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

Histopathology: medullary carcinoma.

Comments: 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 forms small groups resembling a microfollicle. The lack of polarity seen in a microfollicle is the important finding.