case_images: PMC10870123_01
case_images: US findings. A 1.91 cm by 1.79 cm hypoechoic thyroid nodule with central calcification was found in the right lower pole.
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case_images: PMC10870123_01_cro-2024-0017-0001-536444_F01.jpg
case_images: F1
case_images: Bedside ultrasonography scan (US) of the thyroid revealed three parathyroid glands ranging from 1.5 to 2 cm in size, as well as a hypoechoic right lower pole thyroid nodule with central calcification measuring 1.91 by 1.79 cm (shown in Fig. 1).
case_images: Fine-needle aspiration cytology (FNAC) findings. a Sheet of monotonous lesional epithelial cells with crowding, nuclear overlap and occasional traversing capillary (arrow). There is no obvious colloid in the background (Hemacolor stain). b Lesional cells exhibit oncocyte-like morphology with mildly enlarged hyperchromatic nuclei and abundant granular cytoplasm. Occasional endothelial cells of traversing capillaries (arrows) are present (Papanicolaou stain).
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case_images: F2
case_images: In view of the radiological findings, fine-needle aspiration cytology (FNAC) was performed for the suspected thyroid nodule on the same day, which eventually yielded a follicular lesion of undetermined significance (shown in Fig. 2).
case_images: Intraoperative image showing the excised right thyroid nodule containing the right superior parathyroid gland and the three other parathyroid glands.
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case_images: F3
case_images: The remaining 3 parathyroid glands were identified and excised and were clinically hyperplastic (shown in Fig. 3).
case_images: Histopathological findings show parathyroid carcinoma exhibiting capsular and vascular invasion into the thyroid gland, with focal involvement of the circumferential margin. a Tumor demonstrates capsular invasion into adjacent thyroid gland parenchyma. H&E stain, x40 magnification. b Tumor demonstrates capsular invasion into adjacent thyroid gland parenchyma. H&E stain, x100 magnification. c Tumor demonstrates vascular invasion as highlighted by the red arrow. ERG immunohistochemical stain, x100 magnification. d Parathyroid nature of the tumor is confirmed by diffuse strong expression with PTH immunohistochemical study. PTH immunohistochemical stain, x40 magnification.
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case_images: F4
case_images: Histopathological diagnosis of the right hemithyroidectomy specimen containing the right superior parathyroid gland was consistent with that of parathyroid carcinoma (shown in Fig. 4).