Clinical presentation: A 9-year-old girl was referred for aspiration cytology. She had been treated for hypothyroidism for three months. On ultrasound a suspicious nodule was detected but FNA was non-diagnostic.

Palpation: no abnormality.

Laboratory tests: TSH 3.14 mIU/L on daily 50 microgram levothyroxine.

Ultrasonography. The thyroid was minimally hypoechoic and had more hypoechoic areas. There was a more hypoechoic nodule in the lower pole of the right lobe. The lesion has irregular, lobulated margins and numerous microcalcifications. A few microcalcification were found outside the core of the tumor. The intranodular vascularization was irregularly increased.

Cytological pattern corresponded to Hashimoto's thyroiditis. A few non-metaplastic cells contained inclusions.

A combined ultrasound-cytological diagnosis was Hashimoto's thyroiditis and papillary cancer.

Histopathology disclosed papillary cancer and Hashimoto's throiditis.

Comments. 

1. The ultrasound presentation of the nodule is very suspicious for papillary cancer. Indeed, this pattern is almost diagnostic.

2. Although the cytological pattern itself was not fully decisive, we could give a decisive, combined ultrasound-cytological diagnosis.