A nonfunctioning parathyroid cyst occurred in an 8-year-old girl, the
youngest patient reported to have this diagnosis. Most cysts are asymp
tomatic; a few are associated with signs and symptoms of hyperparathyr
oidism. In asymptomatic patients with a lateral neck cyst, aspiration
of clear fluid with an elevated parathyroid hormone level is diagnosti
c of a parathyroid cyst. If this results in disappearance of the cyst.
without recurrence, no further treatment is necessary. If the cyst re
curs, aspiration may be repeated. However, persistence of the cyst des
pite aspiration or recurrence after the second aspiration should promp
t surgical removal, with intraoperative identification of all parathyr
oid glands, because functioning parathyroid cysts are associated with
a high risk of hyperplasia or adenoma.