Session: SUN 234-256-Bone & Calcium Metabolism: Clinical Trials & Case Series
Poster Board SUN-250
Parathyroid Cysts (PCs) are rare entities, representing only <1% of neck masses. A PC may present as an asymptomatic neck mass or may be discovered as an incidental finding during neck surgery or imaging procedures performed for unrelated reasons. True PCs are usually nonfunctional and asymptomatic; however, large PCs can cause dysphagia, pain, tracheal compression, and recurrent laryngeal nerve paralysis. They are often misdiagnosed with thyroid nodules. The diagnosis can be confirmed by the assay of the water-clear fluid for parathyroid hormone (PTH). We present five cases with PC causing primary hyperparathyroidism (PHP) in one patient.
A 30-year-old man presented with dysphonia that started three weeks ago. Ultrasound (USG) demonstrated an anechoic 15x20x30 mm lesion located at posterior of the left thyroid lobe. PTH level was 1983 pg/ml in the aspirated watery cystic fluid. The second patient who is a 25-year-old man with the complaint of left side neck mass was misdiagnosed with thyroid nodule (diameter 27x20x23 mm). Fine needle aspiration (FNA) failed to provide diagnostic tissue however, measurement of PTH in the FNA fluid showed a high concentration (5000 pg/ml) of PTH. A left side cystic structure (diameter 13x14.7x20 mm) adjacent to the left thyroid lobe, whose aspirate had a PTH level of 892 pg/ml, was detected in the third patient who is a 51-year-old woman with primary hypothyroidism. The fourth case is an asymptomatic 46-year-old woman with a 18x19x30 mm cyst that was located at the posterior border of the left thyroid lobe. PTH level was 633.6 pg/ml in the aspirated fluid. All of these four cases have normal serum PTH, calcium and phosphate levels. Also their sestamibi scans showed no focal uptake. Lastly, a 74-year-old female presented with PHPT (serum calcium of 11.7 mg / dl, normal 8.5 – 10.5 mg / dl; PTH 885 pg / ml, normal 15 – 65 pg / ml). USG showed nodular goiter and 16.6x21.7x21 mm cystic mass at the inferoposterior border of the right thyroid lobe. PC could be localized by Tc99m-sestaMIBI.
PCs are rarely seen, but the diagnosis should be considered in a patient with a cystic neck mass, especially occurring in the adjacent lower pole of the thyroid gland. They may be misdiagnosed with thyroid nodules. Fine needle aspiration with estimation of the level of PTH in the aspirate allows the definitive diagnosis to be made. Sestamibi scan may not be reliable in the diagnosis of non-functional parathyroid cysts
Nothing to Disclose: YT, AA, BAD, MMT, SI, DB, SG
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