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Hyperparathyroidism
This case features a patient presenting with hyperparathyroidism, ultimately diagnosed with a parathyroid adenoma.
Imaging overview:
Coronal non-contrast CT demonstrates a hypodense lesion measuring 46 HU relative to the normal thyroid parenchyma. Coronal contrast-enhanced CT at approximately 30 seconds shows avid wash-in with the lesion measuring 400 HU, hyperdense relative to the thyroid. Coronal contrast-enhanced CT at approximately 90 seconds demonstrates wash-out with attenuation decreasing to 250 HU, consistent with the classic enhancement pattern of a parathyroid adenoma.
Clinical insight:
Parathyroid adenomas are the most common cause of primary hyperparathyroidism. On 4D CT, the classic enhancement pattern consists of a hypodense lesion on non-contrast imaging, rapid wash-in on arterial phase becoming hyperdense relative to the thyroid, and wash-out on delayed phase returning to hypodensity. However, this classic pattern is seen in only approximately 20% of cases, so its absence should not exclude the diagnosis. Key information surgeons require from imaging includes the number of abnormal glands, size, and precise anatomic location, including the identification of ectopic glands. A polar or peripheral artery coursing around or into the lesion is an additional imaging feature that can aid localization.
Case courtesy of Mark Manganaro, DO, University of Michigan, and Remy Lobo, MD, University of Michigan, University of Utah.