First examination (first two rows of images)

Clinical data: A 34-year-old woman was referred for the evaluation of a newly discovered nodule.

Palpation: a moderately enlarged right lobe with a nodule in the upper pole.

Functional state: euthyroidism (TSH-level 1.18 mIU/L). 

Ultrasonography: The basic echo structure of the thyroid was normal. There were two hypoechogenic nodules in the right lobe next to each other. The larger one presented pronounced intranodular blood flow and signs of perinodular vascularization. 

Cytological picture. There was no colloid in the background. Thyrocytes occurred in clusters of microfollicles with vascularization. Follicular cells exhibited variability in size but they did not any significant atypia.

Cytological diagnosis follicular tumor with the possibility of autonomously functioning nodule.

Scintigraphy disclosed a "hot" nodule in the upper 2/3 of the right lobe. 

Second examination seven years later (third row of images)

Clinical data: The woman came to routine follow-up examination. She gave birth 18 months ago and except for moderate fatigue she had no complaints.

Palpation: a not firm nodule in the right lobe.

Functional state: euthyroidism with TSH-level 1.07 mIU/L.

Ultrasonography. There was one relevant change compared with the former examination. A new lesion has appeared next to the dorsal part of the larger nodule which proved to an autonomously functioning nodule 5 years ago. This lesion was difficult-to examine because of its location. However, it was deeply hypoechoic and had irregular margins and showed irregularly increased intranodular blood flow. By reviewing the images recorded at the previous examination, we could reveal this lesion. See explanation at the images.

Cytology was performed from this newly detected nodule and resulted in suspicion of papillary cancer.

Histopathology disclosed an encapsulated papillary cancer with 20 mm maximal diameter in the close proximity to a follicular adenoma. At one point, the tumor break through the capsule. The other hypoechoic lesion proved to be a parathyroid adenoma.

Comments.

1. There were two signs favoring the possibility of an autonomously functioning nodule at the first examination. Firstly, the increased intranodular blood flow with perinodular vascularization. Secondly, the vascularization seen on the cytological smear.
2. The parathyroid adenoma was located in an unusual location within the thyroid and was surrounded all along with thyroid tissue.
3. It is worth reviewing the first presentation of the tumor. We can reveal the tumor tissue which did not differ in echogenicity from the autonomously functioning adenoma at the first examination while became more hypoechoic at the second visit.