Clinical presentation: a 26-year-old woman was referred for evaluation of a nodule which was discovered by the patient herself for a month.

Palpation: an elastic nodule in the right lobe.

Functional state: euthyroidism with TSH-level 0.56 mIU/L.

Ultrasonography: the thyroid was echonormal. There was a mixed nodule in the right lobe. The type of the cyst was spongiform with central cystic degeneration. The lesion presented halo sign and a type 2 vascular pattern.

Cytology was performed. Only macrophages and blood cells were on the smear made from 1 mL brown fluid. Six months later we repeated the aspiration and gained 1.2 mL brown fluid. The result of the second FNAC was not diagnostic, too.

Final diagnosis: nodular goiter with not greater than 1% risk of malignancy. Considering the ultrasound presentation we told the patient that the risk of malignancy is less than 1% and offered regular follow-up examination.

The patient decided to undergo surgery. Histopathology: benign cystadenoma in the right thyroid.

Comments.

1. In the event of a solitary nodule presenting halo and type 2 vascular pattern, the diagnosis of a follicular tumor is very likely. In contrast with an adenoma, a follicular carcinoma is only exceptionally undergoes spongiform-type cystic degeneration.

2. The risk of malignancy in a spongiform cyst is negligible.