European Journal of Radiology

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1 European Journal of Radiology 82 (2013) Contents lists available at SciVerse ScienceDirect European Journal of Radiology journa l h o me pa ge: Symptomatic nonfunctioning parathyroid cysts: Role of simple aspiration and ethanol ablation Jin Yong Sung a, Jung Hwan Baek a,c,, Kyu Sun Kim a, Ducky Lee b, Eun Ju Ha c, Jeong Hyun Lee c a Department of Radiology, Thyroid Center, Daerim St. Mary s Hospital, # Daerim-dong, Youngdeungpo-gu, Seoul , Republic of Korea b Department of Internal Medicine, Thyroid Center, Daerim St. Mary s Hospital, # Daerim-dong, Youngdeungpo-gu, Seoul , Republic of Korea c Department of Radiology and Research Institute of Radiology, University of Ulsan College of Medicine, Asan Medical Center, 86 Asanbyeongwon-Gil, Songpa-Gu, Seoul , Republic of Korea a r t i c l e i n f o Article history: Received 26 August 2012 Received in revised form 15 October 2012 Accepted 24 October 2012 Keywords: Parathyroid Parathyroid cyst Ethanol ablation Ultrasound Parathyroid hormone a b s t r a c t Objectives: To evaluate the outcomes of simple aspiration and ethanol ablation in the management of symptomatic nonfunctioning parathyroid cyst (PC). Methods: We performed simple aspirations for 12 PCs in 12 patients from March 1997 to June PC was diagnosed if the aspirated fluid was clear colorless and showed an elevated parathyroid hormone (PTH) level. Ethanol ablation (EA) was performed for recurrent PCs. Simple aspirations were performed using 23-gauge needles and EAs using 18-gauge needles with 99% ethanol under ultrasound (US) guidance. We evaluated cyst volume, cosmetic score, symptom score, and complications. Results: Mean follow-up period of all patients was 19.2 ± 12.9 months (median, 15.0 months; range, 7 40 months). Simple aspiration was successful in four patients, and the mean volume reduction after simple aspiration was 98.2 ± 3.5% (range, %). In eight recurrent cases, EA resulted in a significant decrease in volume (P = 0.012), as well as in cosmetic (P = 0.011) and symptom (P = 0.01) scores at last follow-up; however two cases of primary failure of EA was treated by repeat EA. No major complications occurred in any patient. Conclusions: For symptomatic nonfunctioning PCs, simple aspiration could be a first line procedure for diagnosis and treatment, while EA can be a subsequent treatment modality for recurrent cases Elsevier Ireland Ltd. All rights reserved. 1. Introduction Parathyroid cysts (PCs) are reported to develop in 0.5% of parathyroid disease and in 1% of all cystic neck lesions [1,2]. PCs are divided into two categories: functioning and nonfunctioning cysts. Functioning PCs, causing primary hyperparathyroidism, have been treated by surgery [3 5]. Nonfunctioning PCs are true cysts and usually asymptomatic; however, large one can cause symptoms such as neck bulging, dysphasia, pain, tracheal compression, and recurrent laryngeal nerve palsy [1,3,4,6]. Ultrasound (US)-guided simple aspiration is the choice for diagnosis of nonfunctioning PCs [7]. The aspirated fluid from these cysts Abbreviations: PC, parathyroid cyst; US, ultrasound; PTH, parathyroid hormone; EA, ethanol ablation. Corresponding author at: Department of Radiology and Research Institute of Radiology, University of Ulsan College of Medicine, Asan Medical Center, 86 Asanbyeongwon-Gil, Songpa-gu, Seoul , Republic of Korea. Tel.: ; fax: address: radbaek@naver.com (J.H. Baek). is usually clear and colorless [1,7]. Elevated parathyroid hormone (PTH) levels in aspirated fluid is indicative of PC; however, elevated PTH levels do not specify that the PC is of the functioning type [1,4,8,9]. Although simple aspiration has been used as an initial diagnosis and treatment for symptomatic nonfunctioning PCs, recurrent cases after aspiration have been reported [1,3,7,10,11]. In patients with recurrent cysts, repeat aspiration, surgical excision, tetracycline treatment, or ethanol ablation (EA) is performed [5,7,9,12 14]. EA has been also used in the treatment of cystic thyroid nodules and thyroglossal duct cysts [15 17]; however, to the best of our knowledge, there are only two case reports for nonfunctioning PCs treated by EA [5,14]. Therefore, the purpose of this study is to evaluate the role of simple aspiration and EA for symptomatic nonfunctioning PCs. 2. Materials and methods This retrospective study was approved by the institutional review board of Daerim St. Mary s hospital, and the consent for X/$ see front matter 2012 Elsevier Ireland Ltd. All rights reserved.

2 J.Y. Sung et al. / European Journal of Radiology 82 (2013) this study was waved; however written informed consent for US guided aspiration and EA was obtained from all patients prior to each procedure Patient enrollment and assessment before procedure From March 1997 to June 2010, we performed simple aspirations in 12 patients (two men and 10 women; mean age, 47.2 years; range, years) with 12 nonfunctioning PCs. PC was diagnosed if the aspirated fluid was clear colorless with elevated PTH levels in the aspirated fluid [1 3]. All enrolled patients fulfilled the following criteria: (1) nonfunctioning PC without solid component; (2) cosmetic and/or pressure symptoms related to PC; (3) no malignant cells in the cystic fluid and/or cyst wall by cytologic examination; and (4) >6 months follow-up after simple aspiration or EA. US examinations were performed by two radiologists (J.H.B. and J.Y.S.) with 15 and 12 years of experience in thyroid US, respectively. A 10-MHz linear probe on a real-time ultrasound system (Aplio SSA-770A, Toshiba Medical Systems, Otawara-shi, Japan) was used for all procedures. The volume of the PC was calculated with the following equation: V = abc/6, where V is volume; a is the largest diameter; and b and c are the two other perpendicular diameters [18]. At enrollment and at each evaluation, patients were asked to rate their symptoms on a 10-cm visual analog scale as a symptom score (0 10) [19]. The physician evaluated the cosmetic score (grade 1, no palpable mass; grade 2, no cosmetic problem but a palpable mass; grade 3, a cosmetic problem on swallowing only; grade 4, a readily detected cosmetic problem) [19 21] Simple aspiration and EA Simple aspiration and EA were performed by the same radiologists using the same US probe and US machine with the patient in the supine position with mild neck extension. Simple aspiration was performed using a 23-gauge needle (Fig. 1). The internal fluid was aspirated as much as possible (Fig. 2), and the PTH level in the aspirated fluid was then measured. Recurrence was defined as volume of PC > 50% of initial volume and/or incompletely resolved symptoms during the follow-up period. For recurrent cysts after first aspiration, repeat aspiration was attempted, except for patients who preferred EA. We performed EA under local anesthesia with 1% lidocaine. An 18-gauge needle was inserted via the normal thyroid tissue to minimize leakage of ethanol outside the cyst [16]. After aspiration of the cystic fluid, we injected 99% sterile ethanol through the same needle (Fig. 2). The amount of injected ethanol was less than 50% of the aspirated fluid volume. After 10 min with the needle in place, the injected ethanol was removed completely and the needle was withdrawn. The patient remained under observation for 30 min. Repeat EA was performed if the cystic portion of the aspirated volume remained larger than 1 ml and/or clinical symptoms remained incompletely resolved during the follow-up period. We evaluated complications during the procedure. Fig. 1. A 51-year-old man with PC. Axial US images of a parathyroid cyst with a largest diameter of 8.6 cm. (a) Before aspiration, a large PC below the left lower pole of the thyroid gland is noted. (b) Echogenic needle tip (arrow) can be seen in the cystic lumen during aspiration. T, trachea; C, common carotid artery Follow-up The US examinations and cosmetic and symptom scores were evaluated for all patients during the follow-up period in the same manner as before the procedure. US examinations were performed at the 1-, 6-month, or later after initial procedure. In US examination, we evaluated the size and volume of the cysts. The volume reduction was assessed by US imaging and was calculated by the following equation: volume reduction (%) = ([initial volume Fig. 2. A 42-year-old woman with PC. Axial US images of a parathyroid cyst with a largest diameter of 5.2 cm. (a) Recurred PC at 1 month after aspiration. (b) PC is filled with instilled ethanol via an 18-gauge needle (arrow) after complete evacuation of the cystic fluid. T, trachea; C, common carotid artery.

3 318 J.Y. Sung et al. / European Journal of Radiology 82 (2013) Table 1 The baseline characteristics of parathyroid cysts. Patient Age/sex Location of cyst Volume of cyst (ml) Symptoms Cosmetic score Symptom score Aspirated fluid Volume (ml) Color PTH (ng/dl) 1 48/F Left 9.4 Discomfort Clear colorless /F Left 12.7 Neck bulging Clear colorless /F Left 28.7 Neck bulging Clear colorless > /F Left 5.1 Discomfort Clear colorless /F Right 10.2 Discomfort Clear colorless /F Left 29.4 Neck bulging Clear colorless /F Left 89.8 Neck bulging Clear colorless /F Right 20.8 Neck bulging Clear colorless /F Left 25.4 Neck bulging Clear colorless /F Left 20.0 Neck bulging Clear colorless /M Right 32.3 Neck bulging Clear colorless /M Left 60.4 Dysphasia Clear colorless 400 (ml) final volume (ml)] 100)/initial volume (ml) [18,22]. Cosmetic and symptom scores were evaluated in the same manner as before procedure. We evaluated long-term complications during the follow-up period Statistical analysis Statistical analysis was performed with the SPSS statistical software package (version 17.0 for Microsoft Windows). For patients with successful aspiration (n = 4) and EA (n = 8), we used Wilcoxon s signed rank test to compare the variables (changes in volume, cosmetic score, and symptom score) at enrollment and at the last follow-up. The level of significance was defined as P < Results Patient data and baseline characteristics of nonfunctioning PCs are summarized in Table 1. Mean follow-up period of all enrolled patients was 19.2 ± 12.9 months (median, 15.0 months; range, 7 40 months). All patients in our study complained of palpable neck mass, neck bulging, dysphasia, or discomfort. US examination showed no definite solid components in the cysts, and aspiration of internal fluid was possible in all cases. The average amount of aspirated fluid was 26.9 ± 22.8 ml (range, 5 85 ml) and the PTH level in the aspirated fluid of all patients was elevated (range, ng/dl) compared with that of normal serum (range, 0 65 ng/dl). Simple aspiration was successful in four patients and recurrence was detected in eight patients. Among the eight patients with recurring cysts, we performed repeat aspiration in four patients but all were recurred, therefore we performed EA in eight patients. The volume, and cosmetic and symptom scores at initial and last follow-up are summarized in Table Patients who underwent aspiration only Among the 12 patients, a single session of aspiration was curative in four patients. Mean volume reduction after simple aspiration was 98.2 ± 3.5% (range, %). The volume and cosmetic and symptom scores decreased, but there were no statistical significance in these values at last follow-up (mean follow-up, 20.3 ± 18.9 months; median, 13.0 months; range, 7 48 months; Table 2) Patients who underwent EA for recurrent cases Recurrences of aspirated cysts were detected from 1 to 6 months after aspiration. We performed EA in eight recurrent cases after aspiration. Among them, four patients underwent two sessions of simple aspiration. Before EA, the mean volume of the recurrent cysts was 23.7 ± 18.9 ml (range, ml) and the mean cystic fluid aspirated was 20.5 ± 19.7 ml (range, 5 65 ml). The amount of injected ethanol was 6.9 ± 4.7 ml (range, 1 15 ml). Single session of EA was successful in six patients. In two cases, a second session of EA was performed at 1 month and 3 months later, respectively, because of insufficient volume reduction. The volume (P = 0.012) and cosmetic (P = 0.011) and symptom (P = 0.01) scores significantly decreased at last follow-up (mean, 12.8 ± 5.6 months; median, 11.9 months; range, 6 23 months; Table 2) Complications There were no major complications such as voice change, infection, intractable pain, esophageal injury, or tracheal injury. Of the eight patients who underwent EA, five complained of mild pain when the needle was removed from the cyst; however, the pain spontaneously resolved within several minutes. There were no long-term complications related to EA procedure during the followup period. Table 2 Changes in volume and symptom and cosmetic scores after procedure. Characteristics Successful aspiration (n = 4) Ethanol ablation (n = 8) Initial Final b P-Value Initial a Final b P-Value Volume (ml) 20.2 ± ± ± ± Cosmetic score 3.5 ± ± ± ± Symptom score 3.0 ± ± ± ± Volume reduction (%) 98.2 ± ± 0.8 Data are mean ± SD. a Cyst volume before ethanol ablation. b Cyst volume at final follow-up.

4 J.Y. Sung et al. / European Journal of Radiology 82 (2013) Discussion In our study, the aspiration of fluid from nonfunctioning PCs was possible in all 12 patients, of which 33% (4/12) were successfully treated by a simple aspiration alone. Repeat aspiration was not effective in any of the four patients with recurrent cysts; but EA successfully treated all of these cases without major complications. The results of this study suggest that although the success rate of simple aspiration is relatively low (33%) it could be a first line procedure for diagnosis and treatment of PCs, because simple aspiration is easy and inexpensive method. EA can be a next treatment modality for recurrent cases after aspiration. Nonfunctioning PCs should be differentiated from thyroid, thyroglossal duct, and brachial cleft cysts [23]. Although the US features of nonfunctioning PCs are nonspecific, the clear colorless nature of their fluid with high PTH concentration could differentiate them from other types of cysts [1 5]. The majority of nonfunctioning PCs are asymptomatic and unnecessary to treat; however, treatment is necessary for symptomatic nonfunctioning PCs with palpable neck masses or compressive symptoms such as dysphasia, dyspnea, hoarseness, or neck pain [1,3,4,6]. The first attempt at aspirating parathyroid cysts was performed by Clark et al. [1] in Since then, several studies have reported successful treatment by simple aspiration, with therapeutic success rates ranging from 33% to 92% [3,7,10,11,24,25]. In our study, the therapeutic success of simple aspiration was 33%. The wide range of success rates may be due to differences in the definition of success and in the duration of follow-up. Delayed recurrences up to 4 years have been reported [3,26]. In our study, the mean followup duration for the patients with successful aspiration was 20.3 month. When initial aspiration is unsatisfactory, various treatment modalities such as repeat aspiration [3,7,10,11,24], ablation with sclerosing agents [5,7,10 14], and surgical excision [3,24] have been applied. Although successful results of repeat aspiration have been reported [3,11,27], this was not the case in our study. Surgery is curative for recurrent cases [3,24,27], but is often unnecessary since nonfunctioning PCs are rarely cancerous and surgical excision could induce various complications [3,4,13]. More conservative, non-surgical treatments, such as tetracycline and ethanol injection have been reported in limited cases [3,5,7,10 14]. To the best of our knowledge, this study represents the largest experience of EA for the treatment of symptomatic nonfunctioning PCs published to date. EA has been used to treat various neck cysts and tumors [15,16,28]; however, there is concern about leakage of ethanol along the needle track [15]. Sung et al. [16] proposed that inserting the needle through sufficient normal thyroid parenchyma, a technique named the trans-isthmic approach method, could minimize ethanol leakage in the treatment of thyroid cysts. This method is also used for the treatment of partially cystic thyroid nodules using radiofrequency ablation to prevent hot fluid from escaping from the thyroid gland and may reduce complications [29,30]. In our study, there were no major complications by using needle insertion via normal thyroid tissue. In two of eight EA cases, we performed second EA session because of insufficient volume reduction. This is a significant primary failure rate (25%). There were limitations to our study, including its retrospective design and small number of patients. However, symptomatic nonfunctioning PC is rare as shown in previous reports. 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