Cystic areas are not uncommon in parathyroid glands but usually a very small. Clinically detectable cysts of a parathyroid gland are relatively uncommon.
Features of a parathyroid cyst:
(1) painless neck swelling usually interpreted as involving the thyroid gland
(2) more common in women
(3) aspiration shows a cystic lesion containing clear, watery fluid
(4) ultrasound shows a smooth walled cyst that is usually unilocular
(4) chemical analysis of the fluid shows a high concentration of parathyroid hormone (PTH)
Definitive diagnosis involves removal of the cyst and demonstration of parathyroid tissue in its wall. The gland is lined by a single layer of epithelium with a clear cytoplasm.
