Clinical presentation: A 42-yr-old woman requested follow-up evaluation of a thyroid cyst which has been known for 7 years.

Palpation: The right lobe was suspicious having a soft nodule.

Laboratory tests: TSH 1.74 mIU/L.

Ultrasonography. The thyroid was echonormal. There was a cystic nodule in the right lobe. The lesion had spongiform portions. The nodules presented all three possible signs of an extrathyroidal extension. There was a minimally hypoechoic nodule in the left lobe.

Cytology of the nodule in the left lobe resulted in benign follicular proliferation.

Suggestion: ultrasound in 5 years.

Comment.

1. The categorization of the cystic nodule depends on the definition of spongiform nodules: the spongiform areas exceeded 50% but the nodule was not entirely spongiform.
   
2. Great proportion of benign nodule presents signs of a possible extrathyroidal extension because these features are non-specific, this is particularly true for cystic nodules located at the edge of a lobe. The liquid produced often bulges the surface of the thyroid. The contour of this nodule was abutting and bulging and the thyroid capsule was discontinuous.
   
3. The small nodule presented irregular shape but this was not of pathological importance. The hard wall of the carotid artery prevented the nodule from spreading sideways.