PMC8130706_01
(a) Maximum intensity projection image - increased fluorodeoxyglucose avidity in the midline of the neck. (b) Fused axial image - markedly increased metabolic activity in left-sided mass lesion (large single arrow). Another large solid-cystic mass lesion arising from the right lobe of the thyroid gland with mildly increased fluorodeoxyglucose uptake (small double arrow). (c) Axial computed tomography scan of the neck - left-sided mass lesion is not separable from the isthmus of the thyroid, thyroid cartilage, and obstructing the supraglottic larynx. (d) Small soft-tissue parenchymal nodules in the lingular segment of the left lung with minimally increased metabolic activity
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F1
The scan also showed small soft-tissue parenchymal nodules in the middle lobe of the right lung and lingular segment of the left lung with minimally increased FDG avidity [Figure 1].
(a) Neck mass biopsy - H and E x 40 - Poorly differentiated carcinoma with rhabdoid cells. (b) Lung biopsy - H and E x 20 Metastatic follicular carcinoma of thyroid
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F2
PAX8 was equivocal [Figure 2].
Axial section of follow-up positron emission tomography/computed tomography scan shows the partial regression of the metabolically active thyroid mass. The benign lesion in the right lobe of thyroid remains unchanged
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F3
The benign adenomatous right thyroid nodule showed no significant change in the appearance [Figure 3].