Abstract #1394898: Ethanol Sclerosis of Recurrent Intrathyroidal Parathyroid Cyst

Abstract

The incidence of parathyroid cyst varies between 0.08 % and 3.4 %. To date about 300 cases have been reported in the worlds’ literature. Parathyroid cysts may be functional or not, with functionating cysts tending to occur in men and at more advanced ages. Non-functionating parathyroid cysts are typically pure cysts that are usually asymptomatic unless they are large enough to cause compressive type symptoms. The treatment for a functionating parathyroid cyst is primarily surgical. We present the case of a 58-year-old Caucasian female who presented with a recurrent parathyroid cyst first being noted in 1993. Initial FNA drainage was reported to have yielded acellular, clear fluid (amount unknown) and fluid PTH was not assessed. A cycle of cyst re-accumulation and repeat FNA drainage occurred. Subsequent FNA drainage in 2008 yielded 20cc of clear fluid and 16.5 cc in 2013. The incidence of parathyroid cyst varies between 0.08 % and 3.4 %. To date about 300 cases have been reported in the world’s literature (1, 2). Parathyroid cysts may be functional or not, with functionating cysts tending to occur in men and at more advanced ages Non-functionating parathyroid cysts are typically pure cysts that are usually asymptomatic unless they are large enough to cause compressive type symptoms (1). The treatment for a functionating parathyroid cyst is primarily surgical. We present the case of a 58-year-old Caucasian female who presented with a recurrent parathyroid cyst first being noted in 1993. Initial FNA drainage was reported to have yielded acellular, clear fluid. A cycle of cyst reaccumulation and repeat FNA drainage occurred. In 2008, cyst fluid PTH was assessed to be 372 pg/ml. Serum calcium levels were consistently normal between 9.2 – 9.4 mg/dl and serum PTH 23.8 – 34 pg/ml from Oct 2012 through Dec 2017. In June 2017, patient returned with a sensation of left neck pressure. Ultrasound revealed a simple cyst encompassing most of the left thyroid lobe measuring 5.1 x 2.1 x 1.7 cm. To prevent recurrence, ethanol sclerosis of the cyst was performed. Follow up evaluation in 2020 revealed patient to feel well, having normal calcium and thyroid blood tests with US documenting resolution of the left intrathyroidal cyst. While treatment of the functionating parathyroid cysts typically remains surgical, there are additional options for non-functionating parathyroid cysts management to include non-surgical options such as sclerosis with ethanol or possibly tetracycline.