PMC6477493_01
Ultrasonography showed a 19 x 16 mm heterogeneous solid nodule (a), and Doppler ultrasonography revealed a hypervascular nodule (b) at the anterior neck. Ultrasonography showed 23 x 14 mm (right lobe) (c) and 15 x 8 mm (left lobe) (d) smooth isoechoic thyroid nodules including cystic degeneration.
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F1
Ultrasonography showed a smooth heterogeneous tumor at the anterior middle neck, smooth isoechoic thyroid nodules without calcification, and no cervical lymph nodes swelling (Fig. 1).
Contrast-enhanced computed tomography of the neck (a; axial image, b; sagittal image) showed a 20 x 10 x 17 mm homogeneous contrast-enhanced tumor inferior to the hyoid bone (white arrow). The vascular structure in front of the tumor is the anterior jugular vein (yellow arrows). 18F-FDG PET/CT showed high accumulation in the anterior middle neck tumor, with a SUVmax of 12.8 (c; Maximum Intensity Projection image, d; axial PET/CT fusion image [white arrow]).
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F2
Contrast-enhanced CT showed a clear-boundary tumor inferior to the hyoid bone and no cervical lymph metastasis (Fig. 2a, b). She was administered a 336 MBq dose of 18F-FDG and rested quietly for approx. 60 min. 18F-FDG PET/CT showed high accumulation in the anterior middle neck tumor, with a maximum standardized uptake value (SUVmax) of 12.8, but the rest of the tissue showed normal 18F-FDG uptake (Fig. 2c, d).
Hematoxylin-eosin staining of the tumor showed normal thyroid tissue and papillary cancer (a x40), and the growth and invasion of cancer with irregular follicular and papillary architectures (b x100). Neoplastic cells showed enlargement of the nuclear groove and eosinophilic cytoplasm (c x400). No thyroglossal duct tissue was found.
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F3
Histopathological findings showed an ETC lacking thyroglossal duct remnants (Fig. 3).