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).

PATIENTS:

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.

METHODS:

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.

RESULTS:

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).

CONCLUSION:

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)