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Thyroglossal duct cyst: a comparison between children and adults
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American Journal of Otolaryngology–Head and Neck Medicine and Surgery 29 (2008) 83 – 87 www.elsevier.com/locate/amjoto
Thyroglossal duct cyst: a comparison between children and adults Shih-Tsang Lin, MDa, Fen-Yu Tseng, MDb, Chuan-Jan Hsu, MDa, Te-Huei Yeh, MDa, Yuh-Shyang Chen, MDa,4 b
Abstract
a Department of Otolaryngology, National Taiwan University Hospital, Taipei, Taiwan Department of Internal Medicine, National Taiwan University Hospital, Taipei, Taiwan Received 14 December 2006
Purpose: The purpose of the study was to evaluate the differences in the clinical characteristics of thyroglossal duct cysts (TGDC) between children and adults and to find a method for optimizing management of TGDC. Materials and methods: This study consisted of a retrospective chart review of patients with a diagnosis of TGDC from 1997 to 2002. All records were reviewed for age and sex, season of first visit, diagnostic methods, sizes and locations of cysts, surgical management, and recurrences. Differences between children and adults were analyzed. Results: A total of 84 patients (32 children, 52 adults) were recruited. There were no significant differences in sex in either group. Compared with children, more adult patients had left-sided and infrahyoid cyst locations. The cyst sizes were significantly larger in adults. In this review, 90.4% of adults and 75% of children underwent a Sistrunk operation, whereas the others underwent cyst excision. There was a total of 5 recurrences, 2 in children and 3 in adults. Conclusion: Although the recurrence rates between children and adults and between different surgical managements were not significantly different, a Sistrunk procedure is recommended as the main operation of choice, especially in adults in whom a more extended tract resection should be performed. D 2008 Published by Elsevier Inc.
1. Introduction Thyroglossal duct cyst (TGDC) has been considered to be the most common congenital midline abnormality in the neck. The cyst usually presents as a painless, slightly mobile, asymptomatic soft mass. Most cysts lie in the midline close to the hyoid bone. However, they can be located at any site along the pathway of descent of the thyroid anlage, thus making the diagnosis of TGDC more difficult. Because of the similar manifestation of the dermoid cyst, lymphadenopathy, and cystic hygroma, Presented at the 8th Taiwan-Japan conference in Otolaryngology, Head and Neck Surgery, Taipei, Taiwan, December 16 to 18, 2005. 4 Corresponding author. Department of Otolaryngology, National Taiwan University Hospital, Taipei 100, Taiwan. Tel.: +886 2 23123456x5216; fax: +886 2 2341 0905. E-mail address: [email protected] (Y.-S. Chen). 0196-0709/$ – see front matter D 2008 Published by Elsevier Inc. doi:10.1016/j.amjoto.2007.02.003
misdiagnoses have been made, and inadvertent removal of an ectopic thyroid gland has been reported in both children and adults [1,2]. Although TGDCs are usually recognized by the age of 5 years, and 60% of the lesions are diagnosed before age 20 [3], about 7% [4] of the adult population still has this abnormality. Excision of the hyoid bone and cyst was first proposed by Schlange in 1893. This procedure results in a high recurrence rate. The Sistrunk operation, first described in 1920, results in a significantly decreased recurrence rate and has remained as the treatment of choice for TGDC. Despite the large amount of literature supporting the Sistrunk approach, postoperative complication and recurrence have been reported in both children and adults [5,6]. Few reports in the literature have reviewed the differences in clinical presentation and outcomes of surgery between adults and children. The purpose of this study is to
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retrospectively review our experience with TGDC in adults and children and to find any differences in clinical presentation, sex, season of first visit, cyst location, diagnosis methods, and recurrence rate. It is hoped that these results will be useful in predicting outcome and optimizing management of TGDC. 2. Materials and methods A retrospective chart review was performed to evaluate patients with a diagnosis of TGDC in the Department of Otolaryngology, National Taiwan University Hospital, between 1997 and 2002. Ninety-six patients with preoperative diagnosis of TGDC were identified in the medical records within this period. After reviewing surgical pathology reports, we excluded 12 patients with misdiagnoses. Eighty-four patients were recruited and divided into 2 groups: adults (z 15 years) and children (b 15 years). Age, sex, cyst location, size, season at first visit, diagnostic and surgical methodology, and postoperation recurrence were abstracted from chart review. Excel 7.0 for Windows (Microsoft Office Excel 2003 for Windows, Cary, NC) and SAS 10.0 for Windows (SAS, Cary, NC) were used for data management and statistical analysis. Continuous variables were presented as mean F SD. The significance of the difference in clinical characteristics between children and adults was calculated by v 2 test (or Fisher exact test) for categorical variables and Student t test for continuous numerical variables. A P value of less than .05 was considered statistically significant. 3. Results During the study period, a total of 96 patients (36 children, 60 adults) had preoperative diagnosis of TGDC. After operation, 12 (12.5%) patients (4 children and 8 adults) were found to be misdiagnosed. The final diagnosis for those patients included 4 of epidermoid cysts in children; and 3 of ectopic thyroid tissue, 3 of dermoid cyst, 1 of hemorrhage cyst, and 1 of bronchogenic cyst in adults. The
Table 1 Demographic and clinical characteristics of patients in different age groups Children (n = 32) Age (y) Mean F SD Median Sex Male Female Site of cyst Middle Left Right Location of cyst Suprahyoid Over hyoid Infrahyoid Size of cyst (cm) Range Mean F SD Season of first visit Spring Summer Fall Winter
Adults (n = 52)
6.1 F 3.5 5.5
41.3 F 15.0 43.0
18 (56.3%) 14 (43.7%)
31 (59.6%) 21 (40.4%)
31 (96.9%) 1 (3.1%) 0
38 (73.1%) 14 (26.9%) 0
12 (37.5%) 8 (25%) 12 (37.5%)
3 (5.8%) 13 (25%) 36 (69.2%)
0.5-4 1.9 F 0.7
0.5-8 2.6 F 1.5
P4
.7613
.0069
.0007
.0181
.983 8 13 8 4
(25%) (37.5%) (25%) (12.5%)
13 18 12 9
(25%) (35%) (23%) (17%)
4 The significance of the difference in clinical characteristics between the children and adults was calculated by v 2 test (or Fisher exact test) for categorical variables and Student t test for continuous numerical variables. A P value of less than .05 was considered statistically significant.
remaining 84 patients (32 children, 52 adults) had histopathologic reports consistent with the presence of a TGDC. They were recruited as study subjects. 3.1. Age The age at presentation ranged from 2 months to 72 years (27.9 F 20.9 years). The mean age was 6.1 F 3.5 years in children and 41.3 F 15.0 years in adults. Fifty percent (16/ 32) of children presented with TGDC before 5 years of age. In adults, TGDC was more frequently found between the ages of 21 and 30 years (14/52, 26.9%) and between 41 and 50 years (15/52, 28.8%). The occurrence in patients older than 65 years was rare (2/52, 3.8%) (Fig. 1). 3.2. Sex The group of children included 18 (56.3%) male and 14 (43.7%) female. Among the adults, 31 (59.6%) were male, and 21 (40.4%) were female. There was no significant difference in sex between the children and adults (v 2, P = .7613) (Table 1). Table 2 Preoperative studies in different age groups Neck CT Thyroid ultrasonography Radioisotope thyroid scanning FNA Thyroid function test
Fig. 1. Age distribution according to initial diagnosis of TGDCs.
4 P = .0104, v 2 test. P = .0035, Fisher exact test.
y
Children (n = 32)
Adults (n = 52)
7 12 4 1 3
26 12 15 15 7
(21.9%)4 (37.5%) (12.5%) (3.1%)y (9.4%)
(50%)4 (23.1%) (28.9%) (28.9%)y (13.5%)
S.-T. Lin et al. / American Journal of Otolaryngology–Head and Neck Medicine and Surgery 29 (2008) 83 – 87
3.3. Location and size The most common clinical presentation of TGDC is a midline neck mass, seen in 69 (82.1%) patients. Compared with children, a higher percentage of adults had their cysts with left-side deviation (26.9% vs 3.1%) and infrahyoid location (69.2% vs 37.5%). The cyst size in the children was 1.9 F 0.7 cm (0.5-4 cm), whereas it was 2.6 F 1.5 cm (0.58 cm) in adults (Student t test, P = .0181) (Table 1).
in children after cyst excision and 3 (5.8%) in adults after the Sistrunk operation (Table 3). The recurrence rates were not statistically different between those 2 surgical methods or between children and adults ( P N .05). All the patients who had recurrences underwent the Sistrunk operation again, and a more extensive tissue resection toward the foramen caecum was performed. 4. Discussion
3.4. Season of the first visit Patients with TGDC, regardless of age, were more likely to have their first visits in the summer than in the winter (Table 1). However, the distribution for the season of the first visit was not significantly different between adults and children (v 2 test, P = .983). 3.5. Preoperative assessment The preoperative studies performed are listed in Table 2. The most frequent preoperative study in adults was computed tomography (CT) (50%), whereas it was thyroid ultrasonography (37.5%) in children. Neck CT scan and fine-needle aspiration (FNA) examinations were more frequently performed in the adult group than in children (CT: v 2 test, P = .0104; FNA: Fisher exact test, P = .0035). 3.6. Surgery and recurrence For surgery, there is a choice between the Sistrunk operation and cyst excision. Seventy-one (84.5%) patients received the Sistrunk operation, and 13 (15.5%) patients received cyst excision (Table 3). The percentage of patients who received the Sistrunk operation was higher in adults than in children (90.4% vs 75%). There were no major complications resulting from surgical intervention. Only 2 hematoma formations in the adult group and 1 local wound infection in the children were identified. Five patients had postoperative recurrence of TGDC: 2 (6.3%) Table 3 Recurrence rates in different age groups with different surgical managements
Sistrunk operation Cystectomy
85
Children (n = 32)
Adults (n = 52)
With recurrence
No recurrence
With recurrence
No recurrence
0
24
3
44
2
6
0
5
The difference in recurrence rates between children and adults was statistically nonsignificant (Fisher exact test, P = 1.0). The difference in recurrence rates between patients with different management was statistically nonsignificant (Fisher exact test, P = .1691). For children only, the difference in recurrence rates between patients with different management was statistically nonsignificant (Fisher exact test, P = .0565). For adults only, the difference in recurrence rates between patients with different management was statistically nonsignificant (Fisher exact test, P = 1.0). For Sistrunk operation only, the difference in recurrence rates between different age groups was statistically nonsignificant (Fisher exact test, P = .5641). For cystectomy only, the difference in recurrence rates between different age groups was statistically nonsignificant (Fisher exact test, P = .4872).
Thyroglossal duct cysts are the most common midline congenital neck mass. It accounts for approximately 70% of congenital neck abnormalities [7]. Thyroglossal duct cysts can be observed at any age. Because it is a congenital malformation, one may expect that the cyst predominates in childhood. In Allard’s [8] meta-analysis, TGDC incidence was found to be higher in children than in adults, whereas in the series of Brousseau et al [9], TGDC was found to be more frequent in adults than in children (66.1% vs 33.9%). Our series similarly shows a more frequent occurrence in adults (62% vs 38%). The different results may be due to the age recorded being at the time of onset or at the time of initial diagnosis. In the meta-analysis series of 1316 cases [8], 31.5% of the patients were younger than 10 years, and 34.6% were older than 30 years. In our series, these numbers are 32% and 40.5%, respectively. Gorlin et al [3] previously reported a 60% occurrence of TGDC in the first 2 decades of life, and in our series, a 60% occurrence was found in the first 3 decades. It seems that there is little difference in terms of geography. Most TGDCs are situated in the midline, and 10% to 24% are located laterally, often to the left [4,10]. It is likely that this lateral presentation may cause confusion in diagnosis. We demonstrated that 69 (82%) patients presented in the midline of the neck and 15 (18%) patients presented in the left paramedian neck. We also showed that patients with left-side–deviated neck mass were more likely to be adults than children, a finding that contrasts that of Brousseau et al [9], who reported equality in both groups. The greater occurrence of left-side deviation in adults may be because the embryological descending pathway of the thyroid tissue lies to the left side [10], and if this mass persists in a descending location with age, there would be a higher chance for the TGDC to be found in adults. About 70% to 80% of patients in Allard’s [8] series had a TGDC located below the hyoid bone. Ahuja et al [11] reported 47.8% infrahyoid TGDC in children and 82.5% in adults [12]. Brousseau et al [9] reported a greater frequency of over-the-hyoid level in children. Our study revealed that infrahyoid TGDC occurred more frequently in adults than in children. The cyst location significantly differed between children and adults. Although the cyst may fluctuate in size, it is usually 1 to 2 cm in diameter. In this series, the cyst was found to be larger in adults than in children, which may indicate that the mass increases with age.
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No previous report addressed the occurrence of TGDC in different seasons. In this study, we found that more cases occurred in the summer, but this was not statistically significant. The distribution of season of first visit was similar in both groups. To elucidate the association between seasons and occurrence of TGDC, more samples are required for further analysis. Opinions regarding preoperative evaluations in cases of suspected TGDC varied in clinical practice. In our series, 5 main diagnostic methods were used in the preoperative workup for TGDC. These include neck CT, thyroid ultrasonography, FNA, radioisotope thyroid scanning, and thyroid function test. Neck CT is an excellent diagnostic tool for the evaluation of a neck mass. It may offer useful information about the cyst location, size, and relation to surrounding structures. Sometimes, even a lingual thyroid can be demonstrated clearly by neck CT. With its relatively reasonable cost and high yield of useful diagnostic information, neck CT is the most common diagnostic tool in the clinic for adults. In children, CT scans are not as frequently performed as in adults because children often require sedation to undergo a scan. Thyroid ultrasonography was the most common test ordered in children in our series because it is the most noninvasive imaging method, does not require sedation, and is cost-effective. It also offers valuable information, for the identification of both the cyst and thyroid gland. If any solid element within the cyst was found, the FNA could be performed under echoguidance to identify the possibility of malignancy in the cyst. The disadvantage of ultrasonography may include its lack of specificity, a 5% false-positive rate [13], and the limitation that it cannot indicate if a lesion is functional or nonfunctional. In addition, it has been demonstrated that an ectopic lingual thyroid could not be identified using this method [13]. Fine-needle aspiration is a very useful tool for the differential diagnosis of cyst lesions from a consistent mass, such as ectopic thyroid tissue, lipoma, lymphadenopathy, or even carcinoma. It has a diagnostic sensitivity of 62% and a positive-predictive value of 69% for the diagnosis of TGDC [7]. With concern to possible injury, FNA is not so popular for diagnosing TGDC in children. Radioisotope thyroid scanning was performed for the possibility of ectopic thyroid tissue as a midline neck mass. It was not routinely used in the clinic for the scanning that involved intravenous administration of radiopharmaceutical compounds, the use of which should be minimized if possible. The thyroid functional test was not a routine test in this series, particularly if the patient was clinically euthyroid and had no history of thyroid dysfunction. With neck CT, thyroid ultrasonography, and/or FNA, most of the differential diagnosis for a cyst or a consistent mass can be made clearly. However, difficulties may exist in differential diagnosis of an ectopic thyroid tissue with cystic or hemorrhagic change from TGDC. In the literature, the incidence of ectopic thyroid tissue was reported to be 1% to 2% [1,2]. Our clinical experience
showed that the actual incidence of solitary ectopic thyroid tissue is around 3.1% (3/96). The possibility of ectopic thyroid should always be kept in mind by the surgeon. Before operation for the cystic lesion, we should confirm whether a normal thyroid gland exists in its original location and check for any unusual thyroid functions, if patient has history of thyroid dysfunction. Usually, this criterion was used to minimize risks of postoperative hypothyroidism, which might be caused by inadvertent removal of the only thyroid tissue presenting as TGDC. Magnetic resonance imaging can accurately delineate the anatomy of a lesion, especially for a large cyst. Magnetic resonance imaging is not recommended in our study for its high cost and because the previously described methods can offer valuable information in most cases. In 1893, Schlange first proposed treating TGDCs by resectioning the central portion of the hyoid bone (a procedure that had a recurrence rate of 20%) [14]. In 1920, Walter Ellis Sistrunk described the surgical management of this congenital abnormality, and this remains the classic basic reference. The Sistrunk operation consists of an en bloc cystectomy, central hyoidectomy, and tract excision up to the foramen caecum. The recurrence rate after the original Sistrunk operation is around 3% to 4% [15,16], and it is the most common technique performed for TGDC today. Simple cyst excision is performed only if the track is not identified at the posterior margin of the hyoid. In this instance, the cord of tissue around the tract is ligated by sutures, cut down, and cauterized. In our series, 5 patients (2 children, 3 adults) had TGDC recurrence. All 3 cases of recurrence in adults received the Sistrunk operation, whereas the 2 cases of recurrence in children received cystectomy. The difference between recurrence rates in children and adults did not differ significantly. The difference in the recurrence rates between Sistrunk operation and cystectomy was also nonsignificant. In children, those who received cystectomy had a higher TGDC recurrence rate than those who received Sistrunk operation. The difference in recurrence rate is statistically nonsignificant (Fisher exact test, P = .0565). However, this result would be best analyzed by a meta-analysis with a larger sample size. Basically, the Sistrunk operation is the operation of choice when dealing with TGDC. We would like to suggest Sistrunk operation rather than cystectomy both for children and adults. 5. Conclusion There is no significant sex difference in the occurrence of TGDC in children and adults. A higher incidence of TGDC was found in adults. Adults had more frequent left-sided and infrahyoid locations of TGDC. The mass was larger in adults. The neck CT scan is useful for the differential diagnosis of the neck mass in adults, whereas thyroid ultrasonography is suitable for the evaluation of the neck mass in children. We recommend performing the complete
S.-T. Lin et al. / American Journal of Otolaryngology–Head and Neck Medicine and Surgery 29 (2008) 83 – 87
Sistrunk procedure for all cases of TGDC, especially in adults in whom the resection of the central hyoid includes a cuff of tongue musculature that should be extended toward the foramen caecum. References [1] Radkowski D, Arnold J, Healy GB, et al. Thyroglossal duct remnants. Preoperative evaluation and management. Arch Otolaryngol Head Neck Surg 1991;117:1378 - 81. [2] Tunkel DE, Domenach EE. Radioisotope scanning of the thyroid gland prior to thyroglossal duct cyst excision. Arch Otolaryngol Head Neck Surg 1998;124:597 - 9. [3] Gorlin RJ, Goldman HM, Hurt W. Thoma’s oral pathology. J Periodontol 1972;43:575 - 7. [4] Dedivitis RA, Camargo DL, Peixoto GL, et al. Thyroglossal duct: a review of 55 cases. J Am Coll Surg 2002;194:274 - 7. [5] Maddalozzo J, Venkatesan TK, Gupta P. Complications associated with the Sistrunk procedure. Laryngoscope 2001;111:119 - 23. [6] Flageole H, Laberge JM, Nguyen LT, et al. Reoperation for cysts of the thyroglossal duct. Can J Surg 1995;38:255 - 9.
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[7] Shahin A, Burroughs FH, Kirby JP, et al. Thyroglossal duct cyst: a cytopathologic study of 26 cases. Diagn Cytopathol 2005;33:365 - 9. [8] Allard RH. The thyroglossal cyst. Head Neck Surg 1982;5:134 - 46. [9] Brousseau VJ, Solares CA, Xu M, et al. Thyroglossal duct cysts: presentation and management in children versus adults. Int J Pediatr Otorhinolaryngol 2003;67:1285 - 90. [10] Macdonald DM. Thyroglossal cyst and fistula. Int J Oral Surg 1974;3:342 - 6. [11] Ahuja AT, King AD, King W, et al. Thyroglossal duct cysts: sonographic appearances in adults. AJNR Am J Neuroradiol 1999;20:579 - 82. [12] Ahuja AT, King AD, Metreweli C. Sonographic evaluation of thyroglossal duct cysts in children. Clin Radiol 2000;55:770 - 4. [13] Gupta P, Maddalozzo J. Preoperative sonography in presumed thyroglossal duct cysts. Arch Otolaryngol Head Neck Surg 2001;127:200 - 22. [14] Turkyilmaz Z, Sonmez K, Karabulut R, et al. Management of thyroglossal duct cysts in children. Pediatr Int 2004;46:77 – 80. [15] Athow AC, Fagg NLK, Drake DP. Management of thyroglossal cysts in children. Br J Surg 1989;76:811 - 4. [16] Bennett KG, Organ CH, Williams GR. Is the treatment for thyroglossal duct cysts too extensive? Am J Surg 1986;152:602 - 5.
American Journal of Otolaryngology–Head and Neck Medicine and Surgery 29 (2008) 83 – 87 www.elsevier.com/locate/amjoto
Thyroglossal duct cyst: a comparison between children and adults Shih-Tsang Lin, MDa, Fen-Yu Tseng, MDb, Chuan-Jan Hsu, MDa, Te-Huei Yeh, MDa, Yuh-Shyang Chen, MDa,4 b
Abstract
a Department of Otolaryngology, National Taiwan University Hospital, Taipei, Taiwan Department of Internal Medicine, National Taiwan University Hospital, Taipei, Taiwan Received 14 December 2006
Purpose: The purpose of the study was to evaluate the differences in the clinical characteristics of thyroglossal duct cysts (TGDC) between children and adults and to find a method for optimizing management of TGDC. Materials and methods: This study consisted of a retrospective chart review of patients with a diagnosis of TGDC from 1997 to 2002. All records were reviewed for age and sex, season of first visit, diagnostic methods, sizes and locations of cysts, surgical management, and recurrences. Differences between children and adults were analyzed. Results: A total of 84 patients (32 children, 52 adults) were recruited. There were no significant differences in sex in either group. Compared with children, more adult patients had left-sided and infrahyoid cyst locations. The cyst sizes were significantly larger in adults. In this review, 90.4% of adults and 75% of children underwent a Sistrunk operation, whereas the others underwent cyst excision. There was a total of 5 recurrences, 2 in children and 3 in adults. Conclusion: Although the recurrence rates between children and adults and between different surgical managements were not significantly different, a Sistrunk procedure is recommended as the main operation of choice, especially in adults in whom a more extended tract resection should be performed. D 2008 Published by Elsevier Inc.
1. Introduction Thyroglossal duct cyst (TGDC) has been considered to be the most common congenital midline abnormality in the neck. The cyst usually presents as a painless, slightly mobile, asymptomatic soft mass. Most cysts lie in the midline close to the hyoid bone. However, they can be located at any site along the pathway of descent of the thyroid anlage, thus making the diagnosis of TGDC more difficult. Because of the similar manifestation of the dermoid cyst, lymphadenopathy, and cystic hygroma, Presented at the 8th Taiwan-Japan conference in Otolaryngology, Head and Neck Surgery, Taipei, Taiwan, December 16 to 18, 2005. 4 Corresponding author. Department of Otolaryngology, National Taiwan University Hospital, Taipei 100, Taiwan. Tel.: +886 2 23123456x5216; fax: +886 2 2341 0905. E-mail address: [email protected] (Y.-S. Chen). 0196-0709/$ – see front matter D 2008 Published by Elsevier Inc. doi:10.1016/j.amjoto.2007.02.003
misdiagnoses have been made, and inadvertent removal of an ectopic thyroid gland has been reported in both children and adults [1,2]. Although TGDCs are usually recognized by the age of 5 years, and 60% of the lesions are diagnosed before age 20 [3], about 7% [4] of the adult population still has this abnormality. Excision of the hyoid bone and cyst was first proposed by Schlange in 1893. This procedure results in a high recurrence rate. The Sistrunk operation, first described in 1920, results in a significantly decreased recurrence rate and has remained as the treatment of choice for TGDC. Despite the large amount of literature supporting the Sistrunk approach, postoperative complication and recurrence have been reported in both children and adults [5,6]. Few reports in the literature have reviewed the differences in clinical presentation and outcomes of surgery between adults and children. The purpose of this study is to
84
S.-T. Lin et al. / American Journal of Otolaryngology–Head and Neck Medicine and Surgery 29 (2008) 83 – 87
retrospectively review our experience with TGDC in adults and children and to find any differences in clinical presentation, sex, season of first visit, cyst location, diagnosis methods, and recurrence rate. It is hoped that these results will be useful in predicting outcome and optimizing management of TGDC. 2. Materials and methods A retrospective chart review was performed to evaluate patients with a diagnosis of TGDC in the Department of Otolaryngology, National Taiwan University Hospital, between 1997 and 2002. Ninety-six patients with preoperative diagnosis of TGDC were identified in the medical records within this period. After reviewing surgical pathology reports, we excluded 12 patients with misdiagnoses. Eighty-four patients were recruited and divided into 2 groups: adults (z 15 years) and children (b 15 years). Age, sex, cyst location, size, season at first visit, diagnostic and surgical methodology, and postoperation recurrence were abstracted from chart review. Excel 7.0 for Windows (Microsoft Office Excel 2003 for Windows, Cary, NC) and SAS 10.0 for Windows (SAS, Cary, NC) were used for data management and statistical analysis. Continuous variables were presented as mean F SD. The significance of the difference in clinical characteristics between children and adults was calculated by v 2 test (or Fisher exact test) for categorical variables and Student t test for continuous numerical variables. A P value of less than .05 was considered statistically significant. 3. Results During the study period, a total of 96 patients (36 children, 60 adults) had preoperative diagnosis of TGDC. After operation, 12 (12.5%) patients (4 children and 8 adults) were found to be misdiagnosed. The final diagnosis for those patients included 4 of epidermoid cysts in children; and 3 of ectopic thyroid tissue, 3 of dermoid cyst, 1 of hemorrhage cyst, and 1 of bronchogenic cyst in adults. The
Table 1 Demographic and clinical characteristics of patients in different age groups Children (n = 32) Age (y) Mean F SD Median Sex Male Female Site of cyst Middle Left Right Location of cyst Suprahyoid Over hyoid Infrahyoid Size of cyst (cm) Range Mean F SD Season of first visit Spring Summer Fall Winter
Adults (n = 52)
6.1 F 3.5 5.5
41.3 F 15.0 43.0
18 (56.3%) 14 (43.7%)
31 (59.6%) 21 (40.4%)
31 (96.9%) 1 (3.1%) 0
38 (73.1%) 14 (26.9%) 0
12 (37.5%) 8 (25%) 12 (37.5%)
3 (5.8%) 13 (25%) 36 (69.2%)
0.5-4 1.9 F 0.7
0.5-8 2.6 F 1.5
P4
.7613
.0069
.0007
.0181
.983 8 13 8 4
(25%) (37.5%) (25%) (12.5%)
13 18 12 9
(25%) (35%) (23%) (17%)
4 The significance of the difference in clinical characteristics between the children and adults was calculated by v 2 test (or Fisher exact test) for categorical variables and Student t test for continuous numerical variables. A P value of less than .05 was considered statistically significant.
remaining 84 patients (32 children, 52 adults) had histopathologic reports consistent with the presence of a TGDC. They were recruited as study subjects. 3.1. Age The age at presentation ranged from 2 months to 72 years (27.9 F 20.9 years). The mean age was 6.1 F 3.5 years in children and 41.3 F 15.0 years in adults. Fifty percent (16/ 32) of children presented with TGDC before 5 years of age. In adults, TGDC was more frequently found between the ages of 21 and 30 years (14/52, 26.9%) and between 41 and 50 years (15/52, 28.8%). The occurrence in patients older than 65 years was rare (2/52, 3.8%) (Fig. 1). 3.2. Sex The group of children included 18 (56.3%) male and 14 (43.7%) female. Among the adults, 31 (59.6%) were male, and 21 (40.4%) were female. There was no significant difference in sex between the children and adults (v 2, P = .7613) (Table 1). Table 2 Preoperative studies in different age groups Neck CT Thyroid ultrasonography Radioisotope thyroid scanning FNA Thyroid function test
Fig. 1. Age distribution according to initial diagnosis of TGDCs.
4 P = .0104, v 2 test. P = .0035, Fisher exact test.
y
Children (n = 32)
Adults (n = 52)
7 12 4 1 3
26 12 15 15 7
(21.9%)4 (37.5%) (12.5%) (3.1%)y (9.4%)
(50%)4 (23.1%) (28.9%) (28.9%)y (13.5%)
S.-T. Lin et al. / American Journal of Otolaryngology–Head and Neck Medicine and Surgery 29 (2008) 83 – 87
3.3. Location and size The most common clinical presentation of TGDC is a midline neck mass, seen in 69 (82.1%) patients. Compared with children, a higher percentage of adults had their cysts with left-side deviation (26.9% vs 3.1%) and infrahyoid location (69.2% vs 37.5%). The cyst size in the children was 1.9 F 0.7 cm (0.5-4 cm), whereas it was 2.6 F 1.5 cm (0.58 cm) in adults (Student t test, P = .0181) (Table 1).
in children after cyst excision and 3 (5.8%) in adults after the Sistrunk operation (Table 3). The recurrence rates were not statistically different between those 2 surgical methods or between children and adults ( P N .05). All the patients who had recurrences underwent the Sistrunk operation again, and a more extensive tissue resection toward the foramen caecum was performed. 4. Discussion
3.4. Season of the first visit Patients with TGDC, regardless of age, were more likely to have their first visits in the summer than in the winter (Table 1). However, the distribution for the season of the first visit was not significantly different between adults and children (v 2 test, P = .983). 3.5. Preoperative assessment The preoperative studies performed are listed in Table 2. The most frequent preoperative study in adults was computed tomography (CT) (50%), whereas it was thyroid ultrasonography (37.5%) in children. Neck CT scan and fine-needle aspiration (FNA) examinations were more frequently performed in the adult group than in children (CT: v 2 test, P = .0104; FNA: Fisher exact test, P = .0035). 3.6. Surgery and recurrence For surgery, there is a choice between the Sistrunk operation and cyst excision. Seventy-one (84.5%) patients received the Sistrunk operation, and 13 (15.5%) patients received cyst excision (Table 3). The percentage of patients who received the Sistrunk operation was higher in adults than in children (90.4% vs 75%). There were no major complications resulting from surgical intervention. Only 2 hematoma formations in the adult group and 1 local wound infection in the children were identified. Five patients had postoperative recurrence of TGDC: 2 (6.3%) Table 3 Recurrence rates in different age groups with different surgical managements
Sistrunk operation Cystectomy
85
Children (n = 32)
Adults (n = 52)
With recurrence
No recurrence
With recurrence
No recurrence
0
24
3
44
2
6
0
5
The difference in recurrence rates between children and adults was statistically nonsignificant (Fisher exact test, P = 1.0). The difference in recurrence rates between patients with different management was statistically nonsignificant (Fisher exact test, P = .1691). For children only, the difference in recurrence rates between patients with different management was statistically nonsignificant (Fisher exact test, P = .0565). For adults only, the difference in recurrence rates between patients with different management was statistically nonsignificant (Fisher exact test, P = 1.0). For Sistrunk operation only, the difference in recurrence rates between different age groups was statistically nonsignificant (Fisher exact test, P = .5641). For cystectomy only, the difference in recurrence rates between different age groups was statistically nonsignificant (Fisher exact test, P = .4872).
Thyroglossal duct cysts are the most common midline congenital neck mass. It accounts for approximately 70% of congenital neck abnormalities [7]. Thyroglossal duct cysts can be observed at any age. Because it is a congenital malformation, one may expect that the cyst predominates in childhood. In Allard’s [8] meta-analysis, TGDC incidence was found to be higher in children than in adults, whereas in the series of Brousseau et al [9], TGDC was found to be more frequent in adults than in children (66.1% vs 33.9%). Our series similarly shows a more frequent occurrence in adults (62% vs 38%). The different results may be due to the age recorded being at the time of onset or at the time of initial diagnosis. In the meta-analysis series of 1316 cases [8], 31.5% of the patients were younger than 10 years, and 34.6% were older than 30 years. In our series, these numbers are 32% and 40.5%, respectively. Gorlin et al [3] previously reported a 60% occurrence of TGDC in the first 2 decades of life, and in our series, a 60% occurrence was found in the first 3 decades. It seems that there is little difference in terms of geography. Most TGDCs are situated in the midline, and 10% to 24% are located laterally, often to the left [4,10]. It is likely that this lateral presentation may cause confusion in diagnosis. We demonstrated that 69 (82%) patients presented in the midline of the neck and 15 (18%) patients presented in the left paramedian neck. We also showed that patients with left-side–deviated neck mass were more likely to be adults than children, a finding that contrasts that of Brousseau et al [9], who reported equality in both groups. The greater occurrence of left-side deviation in adults may be because the embryological descending pathway of the thyroid tissue lies to the left side [10], and if this mass persists in a descending location with age, there would be a higher chance for the TGDC to be found in adults. About 70% to 80% of patients in Allard’s [8] series had a TGDC located below the hyoid bone. Ahuja et al [11] reported 47.8% infrahyoid TGDC in children and 82.5% in adults [12]. Brousseau et al [9] reported a greater frequency of over-the-hyoid level in children. Our study revealed that infrahyoid TGDC occurred more frequently in adults than in children. The cyst location significantly differed between children and adults. Although the cyst may fluctuate in size, it is usually 1 to 2 cm in diameter. In this series, the cyst was found to be larger in adults than in children, which may indicate that the mass increases with age.
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No previous report addressed the occurrence of TGDC in different seasons. In this study, we found that more cases occurred in the summer, but this was not statistically significant. The distribution of season of first visit was similar in both groups. To elucidate the association between seasons and occurrence of TGDC, more samples are required for further analysis. Opinions regarding preoperative evaluations in cases of suspected TGDC varied in clinical practice. In our series, 5 main diagnostic methods were used in the preoperative workup for TGDC. These include neck CT, thyroid ultrasonography, FNA, radioisotope thyroid scanning, and thyroid function test. Neck CT is an excellent diagnostic tool for the evaluation of a neck mass. It may offer useful information about the cyst location, size, and relation to surrounding structures. Sometimes, even a lingual thyroid can be demonstrated clearly by neck CT. With its relatively reasonable cost and high yield of useful diagnostic information, neck CT is the most common diagnostic tool in the clinic for adults. In children, CT scans are not as frequently performed as in adults because children often require sedation to undergo a scan. Thyroid ultrasonography was the most common test ordered in children in our series because it is the most noninvasive imaging method, does not require sedation, and is cost-effective. It also offers valuable information, for the identification of both the cyst and thyroid gland. If any solid element within the cyst was found, the FNA could be performed under echoguidance to identify the possibility of malignancy in the cyst. The disadvantage of ultrasonography may include its lack of specificity, a 5% false-positive rate [13], and the limitation that it cannot indicate if a lesion is functional or nonfunctional. In addition, it has been demonstrated that an ectopic lingual thyroid could not be identified using this method [13]. Fine-needle aspiration is a very useful tool for the differential diagnosis of cyst lesions from a consistent mass, such as ectopic thyroid tissue, lipoma, lymphadenopathy, or even carcinoma. It has a diagnostic sensitivity of 62% and a positive-predictive value of 69% for the diagnosis of TGDC [7]. With concern to possible injury, FNA is not so popular for diagnosing TGDC in children. Radioisotope thyroid scanning was performed for the possibility of ectopic thyroid tissue as a midline neck mass. It was not routinely used in the clinic for the scanning that involved intravenous administration of radiopharmaceutical compounds, the use of which should be minimized if possible. The thyroid functional test was not a routine test in this series, particularly if the patient was clinically euthyroid and had no history of thyroid dysfunction. With neck CT, thyroid ultrasonography, and/or FNA, most of the differential diagnosis for a cyst or a consistent mass can be made clearly. However, difficulties may exist in differential diagnosis of an ectopic thyroid tissue with cystic or hemorrhagic change from TGDC. In the literature, the incidence of ectopic thyroid tissue was reported to be 1% to 2% [1,2]. Our clinical experience
showed that the actual incidence of solitary ectopic thyroid tissue is around 3.1% (3/96). The possibility of ectopic thyroid should always be kept in mind by the surgeon. Before operation for the cystic lesion, we should confirm whether a normal thyroid gland exists in its original location and check for any unusual thyroid functions, if patient has history of thyroid dysfunction. Usually, this criterion was used to minimize risks of postoperative hypothyroidism, which might be caused by inadvertent removal of the only thyroid tissue presenting as TGDC. Magnetic resonance imaging can accurately delineate the anatomy of a lesion, especially for a large cyst. Magnetic resonance imaging is not recommended in our study for its high cost and because the previously described methods can offer valuable information in most cases. In 1893, Schlange first proposed treating TGDCs by resectioning the central portion of the hyoid bone (a procedure that had a recurrence rate of 20%) [14]. In 1920, Walter Ellis Sistrunk described the surgical management of this congenital abnormality, and this remains the classic basic reference. The Sistrunk operation consists of an en bloc cystectomy, central hyoidectomy, and tract excision up to the foramen caecum. The recurrence rate after the original Sistrunk operation is around 3% to 4% [15,16], and it is the most common technique performed for TGDC today. Simple cyst excision is performed only if the track is not identified at the posterior margin of the hyoid. In this instance, the cord of tissue around the tract is ligated by sutures, cut down, and cauterized. In our series, 5 patients (2 children, 3 adults) had TGDC recurrence. All 3 cases of recurrence in adults received the Sistrunk operation, whereas the 2 cases of recurrence in children received cystectomy. The difference between recurrence rates in children and adults did not differ significantly. The difference in the recurrence rates between Sistrunk operation and cystectomy was also nonsignificant. In children, those who received cystectomy had a higher TGDC recurrence rate than those who received Sistrunk operation. The difference in recurrence rate is statistically nonsignificant (Fisher exact test, P = .0565). However, this result would be best analyzed by a meta-analysis with a larger sample size. Basically, the Sistrunk operation is the operation of choice when dealing with TGDC. We would like to suggest Sistrunk operation rather than cystectomy both for children and adults. 5. Conclusion There is no significant sex difference in the occurrence of TGDC in children and adults. A higher incidence of TGDC was found in adults. Adults had more frequent left-sided and infrahyoid locations of TGDC. The mass was larger in adults. The neck CT scan is useful for the differential diagnosis of the neck mass in adults, whereas thyroid ultrasonography is suitable for the evaluation of the neck mass in children. We recommend performing the complete
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Sistrunk procedure for all cases of TGDC, especially in adults in whom the resection of the central hyoid includes a cuff of tongue musculature that should be extended toward the foramen caecum. References [1] Radkowski D, Arnold J, Healy GB, et al. Thyroglossal duct remnants. Preoperative evaluation and management. Arch Otolaryngol Head Neck Surg 1991;117:1378 - 81. [2] Tunkel DE, Domenach EE. Radioisotope scanning of the thyroid gland prior to thyroglossal duct cyst excision. Arch Otolaryngol Head Neck Surg 1998;124:597 - 9. [3] Gorlin RJ, Goldman HM, Hurt W. Thoma’s oral pathology. J Periodontol 1972;43:575 - 7. [4] Dedivitis RA, Camargo DL, Peixoto GL, et al. Thyroglossal duct: a review of 55 cases. J Am Coll Surg 2002;194:274 - 7. [5] Maddalozzo J, Venkatesan TK, Gupta P. Complications associated with the Sistrunk procedure. Laryngoscope 2001;111:119 - 23. [6] Flageole H, Laberge JM, Nguyen LT, et al. Reoperation for cysts of the thyroglossal duct. Can J Surg 1995;38:255 - 9.
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