PMC7924148_01
Neck ultrasound and 99mTc sestamibi scintigraphy parathyroid scan images of the neck. A, Transverse and B, longitudinal ultrasound images of the neck performed at the time of diagnosis, showing a 24 x 21 x 17 mm solid lesion located in the lower pole of the left thyroid lobe. C, Early and D, delayed images of 99mTc sestamibi scintigraphy displaying a high uptake area in the lower pole of the left thyroid lobe, consistent with hyperfunctioning parathyroid tissue (arrow).
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The neck US scan displayed a 24 x 21 x 17 mm highly vascularized mixed cystic/solid thyroid nodule of the left lobe (Fig. 1 A and B). One month after the initial diagnosis, serum calcium level was 12.3 mg/dL, and PTH level was 310 pg/mL. 99mTc sestamibi scintigraphy was performed and showed high uptake in the left posterior thyroid region, suspicious for a parathyroid lesion (Fig. 1 C and D).
18F-choline positron emission tomography/computed tomography scan of the neck. A, Coronal and B, transverse images of low-dose computed tomography scan of the neck. C, D, Positron emission tomography images showing an increased uptake at the lower pole of the left thyroid lobe, consistent with autonomous parathyroid tissue.
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Twenty days after the FNAB, an 18F-choline-positron emission tomography scan was performed, which showed a metabolically active (standardized uptake value, maximum 5.9) hypodense nodule of 23 x 16 x 18 mm below the left thyroid lobe, with extensive necrotic phenomena consistent with a diagnosis of hyperfunctioning parathyroid tissue (Fig. 2).
US of the study patient's neck showing the evolution of the parathyroid lesion during the follow-ups. A, Neck US performed 1 month after the fine-needle aspiration biopsy, displaying a 14 x 19 x 22 mm mixed lesion apparently embedded in the left thyroid lobe (arrow). B, Neck US performed 6 months after the fine-needle aspiration biopsy, showing a 14 x 19 x 14 mm markedly hypoechoic lesion (arrow). C, After 1 year, the lesion showed a further size reduction, measuring 9 x 10 x 13 mm (arrow). US = ultrasonography.
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US showed a slightly hypoechoic nodule of 14 x 19 x 22 mm below the left thyroid lobe, with absent vascularity on color Doppler (Fig. 3 A). Unfortunately, the original cytologic specimen was unavailable, so we were unable to perform a pathologic revision. The neck US revealed a reduction of the lesion to 14 x 19 x 14 mm), which appeared markedly hypo-anechoic (Fig. 3 B). The neck US showed evidence of further dimensional reduction of the lesion, measuring 9 x 10 x 13 mm (Fig. 3 C).