Clinical presentation: A 25-yr-old woman came to a follow-up examination. Aspiration cytology of a nodule with the dimensions of 19x17x26 mm (width, depth, length, respectively) resulted in benign lesion three years ago.

Palpation: a firm, large nodule in the right lobe.

Laboratory test: TSH 2.35 mIU/L.

Ultrasonography. A large nodule occupied almost the entire right lobe. The medial part of the nodule was undulated. Compared with the previous examination the nodule has significantly increased.

Cytology resulted in benign follicular proliferation. Taking the ultrasound pattern into account we gave a common sonographic-cytological diagnosis of follicular tumor.

Right lobectomy was performed. Histopathology disclosed follicular adenoma.

Comment.

1. Small irregularities on the borders should not be overestimated and the extent of irregularities has to be related to the size of the nodule.

2. A large nodule occupying significant part of a lobe has no other chance than to follow the anatomical situation. The dorsomedial protuberance of the nodule is caused by the anatomy: the shape of the nodule simply fits to the shape of the lobe.

3. The contour is abutting at the dorsal part of the nodule while non-abutting at the ventral part. The capsule is continuous at the contact parts.