Ultrasound diagnosis of parathyroid cysts

Cysts of the parathyroid gland are rare, in most cases they are afunctional and misdiagnosed.

They can be accidentally detected during a neck examination for other reasons (thyroid disease).


We present 38 patients with echographic findings of cystic lesions that can be parathyroid cysts. 27 were women, 11 men, mean age 48 years (19-75). Parathyroid function was normal in 29 patients. 9 patients had primary hyperparathyroidism.


We used standard US equipment with linear high resolution probes, 10-17 MHz. Fine needle aspiration biopsy (FNAB) was performed by a „free hand“ technique, using a thin needle of 22 G and a syringe of 20 ml. Parathormone  in aspirated material was determined  with IRMA (Beckman Coulter Inc.). Standard methods were used to determine Ca, P and PTH in serum.


In 15 patients a typical cystic form was echographically found. With FNAB,  a clear, watery liquid, was obtained (few drops to 135 ml), and PTH in aspirate was elevated (2-72 pmo/l).

In 16 patients hypoehogenic forms were found behind the thyroid without internal vascularization. With FNAB thick yellow or reddish content, like colloid, was obtained (few drops to 3 ml). PTH in aspirate was elevated in 9 patients (2 - >150 pmol/l), and in 7 patients PTH was low (0,2,-06 pmol/l), but cytologically parathyroid cells, including in colloid, were found.

In 7 patients, cystic – solid forms were found with or without internal vascularization. With FNAB, and cytological analysis of smears, 2 parathyroid adenoma were confirmed. Parathyroid cells with cystic degeneration were found in 3 aspirates, and in 2 aspirates cells of peripheral blood were found.  PTH was enormously elevated in all cases (43.7- >150 pmol/l).


Ultrasound in combination with FNAB and PTH determination are the methods of choice for detecting parathyroid cysts.

Posted by: Hrvojka Tomic-Brzac, M.D.. Ph.D., University Hospital Centre Zagreb, Croatia (11-Apr-2017)