- Email: [email protected]
Dual thyroid ectopia: A case report and literature review
International Journal of Pediatric Otorhinolaryngology Extra 9 (2014) 160–162
Contents lists available at ScienceDirect
International Journal of Pediatric Otorhinolaryngology Extra journal homepage: www.elsevier.com/locate/ijporl
Case Report
Dual thyroid ectopia: A case report and literature review§ Jonathan M. Melzer *, Thomas Q. Gallagher Department of Otolaryngology-Head and Neck Surgery, Naval Medical Center, Portsmouth, VA, United States
A R T I C L E I N F O
A B S T R A C T
Article history: Received 17 July 2014 Received in revised form 19 September 2014 Accepted 20 September 2014
Ectopic thyroid gland is a type of thyroid dysgenesis which also includes abnormalities such as thyroid hemiagenesis and persistent thyroglossal duct tracts. These abnormalities occur anywhere from 1 in 100,000 to 300,000 live births. Only 30 cases of dual thyroid ectopia have been reported. The authors present a case of dual thyroid ectopia to discuss diagnostic and management strategies. The study is a case report encountered at a tertiary health care center. The etiology, diagnosis, and treatment of dual thyroid ectopia are discussed. Published by Elsevier Ireland Ltd.
Keywords: Dual thyroid ectopia Thyroid dysgenesis Ectopic thyroid Lingual thyroid
1. Case presentation An otherwise healthy three-year-old Asian female was evaluated for an asymptomatic, midline neck mass. Her parents reported no overlying skin changes and she did not appear to have any respiratory distress. The mass had been present since birth and the parents were told that the patient would ‘‘outgrow’’ the mass. She had no significant family history or atypical birth history. Physical exam demonstrated a three-centimeter ballotable midline neck mass with no overlying cutaneous changes and no tenderness on palpation which was mobile and did not elevate with swallowing. There was no palpable lymphadenopathy. Preoperative ultrasound of the neck was obtained which showed a solid mass with possibility for malignancy. Subsequently an MRI was obtained (Figs. 1 and 2) which showed a 2 cm 1.5 cm 1.3 cm solid mass in the midline not adherent to surrounding structures as well as an additional mass at the base of the tongue
§ The views expressed in this article are those of the authors and do not necessarily reflect the official policy or position of the Department of the Navy, Department of Defense, or the United States government. There are no financial conflicts of interest to disclose. I am a military service member. This work was not prepared as part of my official duties. Title 17 U.S.C. 105 provides that ‘Copyright protection under this title is not available for any work of the United States Government.’ Title 17 U.S.C. 101 defines a United States Government work as a work prepared by a military service member or employee of the United States Government as part of that person’s official duties. * Corresponding author at: Department of Otolaryngology-Head and Neck Surgery, Naval Medical Center Portsmouth, 620 John Paul Jones Circle, Portsmouth, VA 23708, United States. Tel.: +1 703 283 8584; fax: +1 757 953 0166. E-mail addresses: [email protected], [email protected] (J.M. Melzer).
http://dx.doi.org/10.1016/j.pedex.2014.09.002 1871-4048/Published by Elsevier Ireland Ltd.
(Fig. 3). The thyroid gland was noted to be ‘‘diminuitive’’ on MRI. An endocrinology evaluation was sought and she was found to be subclinically hypothyroid. Nuclear scintigraphy was performed (Fig. 4) which revealed two areas of increased uptake: one corresponding with the neck mass and the other with the base of tongue lesion. No additional uptake was noted in the native thyroid bed. 2. Embryology and clinical discussion Ectopic thyroid gland is a type of thyroid dysgenesis that also includes abnormalities such as thyroid hemiagenesis and persistent thyroglossal duct cysts or sinuses [1]. These abnormalities occur from 1 in 100,000 to 300,000 live births. Cases of dual thyroid ectopia are much rarer with only 30 cases being reported in the literature. The thyroid gland is derived from endodermal epithelial cells and begins development near gestational day 24 [2]. The bulk of the thyroid gland derives from the median anlage (thyroid follicular cells) that forms at the eventual site of the foramen cecum and descends inferiorly in the midline to eventually reach its adult location between the 2nd and 5th tracheal rings [3]. The remainder of the thyroid gland, including the parafollicular or ‘Ccells’ derives from the fourth pharyngeal pouches and ultimobranchial bodies on either side of midline and merges with the median anlage [3]. The descent of the median thyroid anlage leads to the development of the thyroglossal duct, which normally atrophies by the sixth gestational week [1]. In normal development, the follicular cells are able to trap iodine by gestational week 12 and native thyroid hormone production commences soon after [1]. The exact mechanisms of thyroid dysgenesis remain elusive
J.M. Melzer, T.Q. Gallagher / International Journal of Pediatric Otorhinolaryngology Extra 9 (2014) 160–162
161
Fig. 1. Sagittal MRI. Fig. 3. Sagittal MRI.
Fig. 2. Axial MRI. Fig. 4. Nuclear scintigraphy scan.
although several transcription factors are thought to play a role [3]. Transcription factors TITF1/NKX2-1 and PAX8 are essential at the beginning of organogenesis and it is thought that mutations in genes regulated by these factors can lead to dysgenesis [3]. Clinically, the lingual region is the most common site of thyroid ectopia, occurring in approximately 90% of cases [4]. In the majority of cases, the ectopic thyroid is the only functioning thyroid tissue [4]. Dual thyroid ectopia is almost always characterized by the absence of normal thyroid tissue, although
exceptions have been reported [5]. Other sites of thyroid ectopia can include the submandibular region (thought to represent failure of the lateral anlage to descend), within the thyroglossal duct, mediastinal, intratracheal, or even within the abdomen (struma ovarii, duodenal, pancreatic) [3]. The majority of patients are asymptomatic although some may exhibit dysphagia, dysphonia, or evidence of obstructive sleep apnea if the airway is impinged
162
J.M. Melzer, T.Q. Gallagher / International Journal of Pediatric Otorhinolaryngology Extra 9 (2014) 160–162
upon [3]. Approximately 50% (range 24–60%) of patients with ectopic thyroids are hypothyroid [6]. Presenting age varies from 3 to 71 but is more common in younger ages, females (1.5:1) and those of Asian descent [6,7]. Among cases of dual ectopia, the subhyoid region is the most common location for the second anomalous gland [7]. Diagnosis is usually made by ultrasound of the neck demonstrating an absence of the normal thyroid gland followed by confirmatory imaging. MRI will show homogenous, well-circumscribed masses with minimal vascularity and solid in nature. Scintigraphy is highly recommended in cases of ectopic thyroid with a reported sensitivity of 96% [7]. Management of dual thyroid ectopia is not well established due to the paucity of cases in the literature. Cases have been reported of thyroid carcinoma in dual ectopia [8]. Nevertheless, most authors recommend avoidance of surgical excision, as ectopic tissue is often the only functioning thyroid tissue unless the patient is symptomatic or there is concern for malignancy [3]. Several surgical approaches have been described (transoral, transhyoid, suprahyoid, and lateral pharyngotomy) for the possibility of reimplanting ectopic tissue to prevent hypothyroidism, and thyroid hormone replacement therapy is recommended for those with symptomatic hypothyroidism [3,6]. Observation is an appropriate management strategy for asymptomatic patients who have no evidence of malignancy, and in adults, radioiodine ablation can be considered in symptomatic patients. For lingual ectopic thyroid, a polysomnogram (PSG) can be considered to quantify any obstructive sleep symptoms. Some case reports have described a severe OSA in adults or adolescents but not previously in younger children [9]. Those patients were successfully treated with surgical excision of the ectopic gland. The patient presented was managed conservatively due to the lack of compressive and obstructive symptoms (normal PSG). She
is now clinically hypothyroid and receiving supplementation. She has been followed at interval appointments and has remained asymptomatic. Authors’ contribution Jonathan Melzer: information gathering and manuscript drafting. Thomas Q. Gallagher: manuscript drafting and editing. Acknowledgements There are no financial relationships to disclose. References [1] A. Jain, S. Pathak, Rare developmental abnormalities of thyroid gland, especially multiple ectopia: a review and our experience, Indian J. Nucl. Med. 25 (4) (2010) 143–146. [2] N. Ibrahim, I. Fadeyibi, Ectopic thyroid: etiology, pathology, and management, Hormones 10 (4) (2011) 261–269. [3] G. Noussios, P. Anagnostis, D. Goulis, D. Lappas, K. Natsis, Ectopic thyroid tissue: anatomical, clinical, and surgical implications of a rare entity, Eur. J. Endocrinol. 165 (2011) 375–382. [4] R. Kumar, S. Khullar, R. Gupta, A. Marwah, A. Malhotra, Dual thyroid ectopy: case report and review of the literature, Clin. Nucl. Med. 25 (4) (2000) 253–254. [5] T.S. Huang, H.Y. Chen, Dual thyroid ectopia with a normally located pretracheal thyroid gland: case report and literature review, Head Neck 29 (September (9)) (2007) 885–888. [6] A. Sood, R. Seam, M. Gupta, D. Sharma, P. Bhardwaj, Dual ectopic thyroid: a case report with review of literature, Iran. J. Radiol. 8 (1) (2011) 29–32. [7] A. Sood, V. Sood, D. Sharma, R. Seam, R. Kumar, Thyroid scintigraphy in detecting dual ectopic thyroid: a review, Eur. J. Nucl. Med. Mol. Imaging 35 (2008) 843– 886. [8] U. Ballehaninna, Carcinoma of dual ectopic thyroid gland in a patient with cyanotic congenital heart disease – case report and review of literature, J. Pediatr. Surg. 48 (2013) E1–E4. [9] S. Coman, et al., Lingual thyroid: an unusual and surgically curable cause of sleep apnoea in a male, Sleep Breath. 14 (December (4)) (2010) 377–380.
Contents lists available at ScienceDirect
International Journal of Pediatric Otorhinolaryngology Extra journal homepage: www.elsevier.com/locate/ijporl
Case Report
Dual thyroid ectopia: A case report and literature review§ Jonathan M. Melzer *, Thomas Q. Gallagher Department of Otolaryngology-Head and Neck Surgery, Naval Medical Center, Portsmouth, VA, United States
A R T I C L E I N F O
A B S T R A C T
Article history: Received 17 July 2014 Received in revised form 19 September 2014 Accepted 20 September 2014
Ectopic thyroid gland is a type of thyroid dysgenesis which also includes abnormalities such as thyroid hemiagenesis and persistent thyroglossal duct tracts. These abnormalities occur anywhere from 1 in 100,000 to 300,000 live births. Only 30 cases of dual thyroid ectopia have been reported. The authors present a case of dual thyroid ectopia to discuss diagnostic and management strategies. The study is a case report encountered at a tertiary health care center. The etiology, diagnosis, and treatment of dual thyroid ectopia are discussed. Published by Elsevier Ireland Ltd.
Keywords: Dual thyroid ectopia Thyroid dysgenesis Ectopic thyroid Lingual thyroid
1. Case presentation An otherwise healthy three-year-old Asian female was evaluated for an asymptomatic, midline neck mass. Her parents reported no overlying skin changes and she did not appear to have any respiratory distress. The mass had been present since birth and the parents were told that the patient would ‘‘outgrow’’ the mass. She had no significant family history or atypical birth history. Physical exam demonstrated a three-centimeter ballotable midline neck mass with no overlying cutaneous changes and no tenderness on palpation which was mobile and did not elevate with swallowing. There was no palpable lymphadenopathy. Preoperative ultrasound of the neck was obtained which showed a solid mass with possibility for malignancy. Subsequently an MRI was obtained (Figs. 1 and 2) which showed a 2 cm 1.5 cm 1.3 cm solid mass in the midline not adherent to surrounding structures as well as an additional mass at the base of the tongue
§ The views expressed in this article are those of the authors and do not necessarily reflect the official policy or position of the Department of the Navy, Department of Defense, or the United States government. There are no financial conflicts of interest to disclose. I am a military service member. This work was not prepared as part of my official duties. Title 17 U.S.C. 105 provides that ‘Copyright protection under this title is not available for any work of the United States Government.’ Title 17 U.S.C. 101 defines a United States Government work as a work prepared by a military service member or employee of the United States Government as part of that person’s official duties. * Corresponding author at: Department of Otolaryngology-Head and Neck Surgery, Naval Medical Center Portsmouth, 620 John Paul Jones Circle, Portsmouth, VA 23708, United States. Tel.: +1 703 283 8584; fax: +1 757 953 0166. E-mail addresses: [email protected], [email protected] (J.M. Melzer).
http://dx.doi.org/10.1016/j.pedex.2014.09.002 1871-4048/Published by Elsevier Ireland Ltd.
(Fig. 3). The thyroid gland was noted to be ‘‘diminuitive’’ on MRI. An endocrinology evaluation was sought and she was found to be subclinically hypothyroid. Nuclear scintigraphy was performed (Fig. 4) which revealed two areas of increased uptake: one corresponding with the neck mass and the other with the base of tongue lesion. No additional uptake was noted in the native thyroid bed. 2. Embryology and clinical discussion Ectopic thyroid gland is a type of thyroid dysgenesis that also includes abnormalities such as thyroid hemiagenesis and persistent thyroglossal duct cysts or sinuses [1]. These abnormalities occur from 1 in 100,000 to 300,000 live births. Cases of dual thyroid ectopia are much rarer with only 30 cases being reported in the literature. The thyroid gland is derived from endodermal epithelial cells and begins development near gestational day 24 [2]. The bulk of the thyroid gland derives from the median anlage (thyroid follicular cells) that forms at the eventual site of the foramen cecum and descends inferiorly in the midline to eventually reach its adult location between the 2nd and 5th tracheal rings [3]. The remainder of the thyroid gland, including the parafollicular or ‘Ccells’ derives from the fourth pharyngeal pouches and ultimobranchial bodies on either side of midline and merges with the median anlage [3]. The descent of the median thyroid anlage leads to the development of the thyroglossal duct, which normally atrophies by the sixth gestational week [1]. In normal development, the follicular cells are able to trap iodine by gestational week 12 and native thyroid hormone production commences soon after [1]. The exact mechanisms of thyroid dysgenesis remain elusive
J.M. Melzer, T.Q. Gallagher / International Journal of Pediatric Otorhinolaryngology Extra 9 (2014) 160–162
161
Fig. 1. Sagittal MRI. Fig. 3. Sagittal MRI.
Fig. 2. Axial MRI. Fig. 4. Nuclear scintigraphy scan.
although several transcription factors are thought to play a role [3]. Transcription factors TITF1/NKX2-1 and PAX8 are essential at the beginning of organogenesis and it is thought that mutations in genes regulated by these factors can lead to dysgenesis [3]. Clinically, the lingual region is the most common site of thyroid ectopia, occurring in approximately 90% of cases [4]. In the majority of cases, the ectopic thyroid is the only functioning thyroid tissue [4]. Dual thyroid ectopia is almost always characterized by the absence of normal thyroid tissue, although
exceptions have been reported [5]. Other sites of thyroid ectopia can include the submandibular region (thought to represent failure of the lateral anlage to descend), within the thyroglossal duct, mediastinal, intratracheal, or even within the abdomen (struma ovarii, duodenal, pancreatic) [3]. The majority of patients are asymptomatic although some may exhibit dysphagia, dysphonia, or evidence of obstructive sleep apnea if the airway is impinged
162
J.M. Melzer, T.Q. Gallagher / International Journal of Pediatric Otorhinolaryngology Extra 9 (2014) 160–162
upon [3]. Approximately 50% (range 24–60%) of patients with ectopic thyroids are hypothyroid [6]. Presenting age varies from 3 to 71 but is more common in younger ages, females (1.5:1) and those of Asian descent [6,7]. Among cases of dual ectopia, the subhyoid region is the most common location for the second anomalous gland [7]. Diagnosis is usually made by ultrasound of the neck demonstrating an absence of the normal thyroid gland followed by confirmatory imaging. MRI will show homogenous, well-circumscribed masses with minimal vascularity and solid in nature. Scintigraphy is highly recommended in cases of ectopic thyroid with a reported sensitivity of 96% [7]. Management of dual thyroid ectopia is not well established due to the paucity of cases in the literature. Cases have been reported of thyroid carcinoma in dual ectopia [8]. Nevertheless, most authors recommend avoidance of surgical excision, as ectopic tissue is often the only functioning thyroid tissue unless the patient is symptomatic or there is concern for malignancy [3]. Several surgical approaches have been described (transoral, transhyoid, suprahyoid, and lateral pharyngotomy) for the possibility of reimplanting ectopic tissue to prevent hypothyroidism, and thyroid hormone replacement therapy is recommended for those with symptomatic hypothyroidism [3,6]. Observation is an appropriate management strategy for asymptomatic patients who have no evidence of malignancy, and in adults, radioiodine ablation can be considered in symptomatic patients. For lingual ectopic thyroid, a polysomnogram (PSG) can be considered to quantify any obstructive sleep symptoms. Some case reports have described a severe OSA in adults or adolescents but not previously in younger children [9]. Those patients were successfully treated with surgical excision of the ectopic gland. The patient presented was managed conservatively due to the lack of compressive and obstructive symptoms (normal PSG). She
is now clinically hypothyroid and receiving supplementation. She has been followed at interval appointments and has remained asymptomatic. Authors’ contribution Jonathan Melzer: information gathering and manuscript drafting. Thomas Q. Gallagher: manuscript drafting and editing. Acknowledgements There are no financial relationships to disclose. References [1] A. Jain, S. Pathak, Rare developmental abnormalities of thyroid gland, especially multiple ectopia: a review and our experience, Indian J. Nucl. Med. 25 (4) (2010) 143–146. [2] N. Ibrahim, I. Fadeyibi, Ectopic thyroid: etiology, pathology, and management, Hormones 10 (4) (2011) 261–269. [3] G. Noussios, P. Anagnostis, D. Goulis, D. Lappas, K. Natsis, Ectopic thyroid tissue: anatomical, clinical, and surgical implications of a rare entity, Eur. J. Endocrinol. 165 (2011) 375–382. [4] R. Kumar, S. Khullar, R. Gupta, A. Marwah, A. Malhotra, Dual thyroid ectopy: case report and review of the literature, Clin. Nucl. Med. 25 (4) (2000) 253–254. [5] T.S. Huang, H.Y. Chen, Dual thyroid ectopia with a normally located pretracheal thyroid gland: case report and literature review, Head Neck 29 (September (9)) (2007) 885–888. [6] A. Sood, R. Seam, M. Gupta, D. Sharma, P. Bhardwaj, Dual ectopic thyroid: a case report with review of literature, Iran. J. Radiol. 8 (1) (2011) 29–32. [7] A. Sood, V. Sood, D. Sharma, R. Seam, R. Kumar, Thyroid scintigraphy in detecting dual ectopic thyroid: a review, Eur. J. Nucl. Med. Mol. Imaging 35 (2008) 843– 886. [8] U. Ballehaninna, Carcinoma of dual ectopic thyroid gland in a patient with cyanotic congenital heart disease – case report and review of literature, J. Pediatr. Surg. 48 (2013) E1–E4. [9] S. Coman, et al., Lingual thyroid: an unusual and surgically curable cause of sleep apnoea in a male, Sleep Breath. 14 (December (4)) (2010) 377–380.