Clinical data: a 58-year-old woman was previously referred for an evaluation of a right parotid tumor evolved over months. The aspiration cytology from the parotid confirmed a mucoepidermoid cancer.  Before surgery a thyroid nodule was detected by the patient.

Palpation: a hard tumor in the isthmic part of the right lobe.

Functional state: euthyroidism (TSH 2.18 mIU/L).

Ultrasonography: a large hypoechogenic inhomogeneous nodule occupying almost the whole right lobe and the isthmus. The left thyroid was intact. There was a hypoechogenic inhomogeneous lesion within the right parotid.

Cytology: there were atypical, elongated tumor cells in a dirty background without any structure. Part of the clusters presented vacuolization and a few unequivocal hyperchromatic epithelial cells were found.

Cytological diagnosis: metastasis with great probability.

Histopathology: mucoepidermoid cancer of the parotis with metastasis to the lymph nodes and to the thyroid.

Comment: in most cases a metastatic tumor is less well-differentiated compared with the primary focus. I don't think that this cytological pattern would be very characteristic of a mucoepidermoid carcinoma. Nevertheless, it is worth analyzing the cytological images which present some of the characteristic features of the mucus producing elements of this carcinoma.