Journal of Otolaryngology Head & Neck Surgery Category: Clinical Type: Case Report
Incidental Finding of Lingual Thyroid in an Infant with Hoarseness
- Melissa A Peace1, Caitlin E Fiorillo2, Kim Shimy3, Pamela Mudd4*
- 1 George Washington University School Of Medicine And Health Sciences, Washington, D.C., United States
- 2 Childrens National Medical Center, Washington, D.C., United States
- 3 Childrens National Medical Center, Washington, D.c., United States
- 4 George Washington University School Of Medicine And Health Sciences, Washington, D.C., United States
*Corresponding Author:Pamela Mudd
George Washington University School Of Medicine And Health Sciences, Washington, D.C., United States
Received Date: Jul 04, 2019 Accepted Date: Jul 18, 2019 Published Date: Jul 25, 2019
In 70% of cases the lingual thyroid is the only functional thyroid tissue, leading to the commonality of accompanying hypothyroidism in patients.  The mean age of diagnosis for lingual thyroid is 40 years old, with statistical peaks at 12.5 and 50 years,  with a strong female predominance.  With the implemented universal newborn screening for congenital hypothyroidism lingual thyroid may be identified earlier in life for those who are symptomatic and present with dysphonia or dysphagia or potential respiratory distress likely to warrant further investigation beyond the diagnosis of congenital hypothyroidism. Challenges to diagnose lingual thyroid remain in infants who possess an asymptomatic course or present with associated symptoms only later in life.  Here, we describe the incidental finding of an asymptomatic lingual thyroid in an infant with hoarseness caused by a vocal cord cyst.
Upon gross examination of the oral cavity in the Otolaryngology clinic, no abnormality or mass was observed. On flexible laryngeal endoscopy she was noted to have a left vocal cord cyst and a secondary reactive nodule on the right vocal cord (Figure 1). The exam additionally revealed a smooth cystic appearing mass at the base of the tongue (Figure 2). Review of a prior neck ultrasound conducted by the pediatric Endocrinologist demonstrated the absence of thyroid tissue in the neck, in addition to her known hypothyroidism, lead to a diagnosis of lingual thyroid. At 6 month follow-up, the patient demonstrated spontaneous resolution of her hoarseness and vocal cord cyst, and continued asymptomatic presence of the lingual thyroid (Figure 3).
Figure 3: Six-month follow-up of resolved vocal cyst as visualized in video laryngoscopy.
Following the diagnosis of lingual thyroid, the patient was treated with continued levothyroxine therapy and monitored with coordinated care between general pediatrics, endocrinology, and otolaryngology.
Interestingly, the patient’s lingual thyroid was found not to be causative of the hoarse voice, but rather that the vocal cord cyst was responsible for the vocal abnormality. This was determined upon six-month follow-up, in which the child’s voice abnormality and vocal cord cyst were both absent, despite the persistence of the lingual thyroid. Therefore, the lingual thyroid presentation was asymptomatic and the diagnosis was incidental.
The observed oral mass was diagnosed a lingual thyroid based on clinical history including the evaluation of a neck ultrasound, depicting the absence of a normal, pretracheal thyroid gland, and the clinical history of congenital hypothyroidism. The patient’s initial TSH level of 70.9 μIU/ml may have been suggestive of variable endogenous thyroid hormone production rather than an absent thyroid gland (athyreosis). Infants with athyreosis have a mean TSH of 255 μIU/ml, a level higher than those with ectopic thyroid. Yet variability does occur as TSH level can range from 67-701 μIU/ml for those with athyreosis, which can clinically blur the line between distinguishing infants with an ectopic thyroid or a true absent thyroid.  Further, at the time of diagnosis of congenital hypothyroidism the patient manifested overtreatment symptoms from the standard 50 mcg/day dose for full-term neonates and required reduction to 25 mcg/day.  Since two months of age the patient’s levothyroxine dosage was on the lower end of the guideline spectrum for hypothyroidism at 4 mcg/kg/day (normal 5-7 mcg/kg/day).  In retrospect, the patient’s clinical congenital hypothyroidism history and management plan was suggestive of trace hormone levels produced from an ectopic thyroid. Consultation with the pediatric Endocrinologist involved proved extremely valuable in determining whether further testing was warranted.
In other reported pediatric lingual thyroid cases, clinicians have performed a Technetium scan (Tc-99) to confirm that the lingual mass is representative of thyroid ectopic tissue, as differential diagnosis can include a thyroglossal duct cyst, dermoid cyst, vascular malformation, and valecular cyst. Here we present a case whereby the benefit of performing such imaging was not indicated.  Based on current literature it has been reported that thyroid gland uptake on Tc-99 imaging can be absent once levothyroxine therapy has been initiated. Therefore, in order to properly image the patient, providers would have needed to discontinue the levothyroxine therapy for a period of time to induce her natural hypothyroid state to ensure accuracy of the scan. We deemed it was inappropriate to discontinue the patient’s levothyroxine supplementation given her young age and the well documented role of thyroid hormones impactful role on infant brain development within the literature.  While deeming that a Tc-99 scan was inappropriate at this time, the pediatric providers involved decided to revisit imaging in the future when the patient could safely be taken off of levothyroxine. We suggest considering Tc-99 imaging when patient’s reach three years of age, which has been demonstrated to be when brain development is less impacted by thyroid hormone levels. [14,15] The asymptomatic nature of the patient’s lingual thyroid also assisted the decision not to complete Tc-99 imaging at this time.
In addition, surgical intervention was deemed unnecessary, as the patient’s lingual thyroid remained asymptomatic, and medical management with levothyroxine therapy was continued. Surgical excision with possible auto transplantation of the lingual thyroid is recommended in those patients with significant dysphagia impeding oral intake, airway obstruction, hemorrhage, and other symptomatic presentations. [15,16] About 1% of lingual thyroids can convert to thyroid carcinoma, however, reported cases have occurred only in adults and was not considered concerning at this time given our patient’s young age and low lifetime risk. [17,18] However, pediatric interdisciplinary follow-up will continue to evaluate the status of the lingual thyroid, revisit imaging as she ages, and discuss possible surgical indications if warranted.
Congenital hypothyroidism is an entity not commonly encountered by a Pediatric Otolaryngologist. Laryngoscopy is performed for many indications in infants, and therefore an understanding of the pediatric lingual thyroid and variable presentation in congenital hypothyroidism can aid in differential diagnosis when a base of tongue mass is encountered.  Further, asymptomatic lingual thyroid, as described in this case is rarely reported in current literature. This case exemplifies the use of an interdisciplinary approach to successfully identify a lingual thyroid in a patient with congenital hypothyroidism, which involved general pediatrics, pediatric endocrinology and pediatric otolaryngology. Importantly, primary-care pediatricians should keep this clinical entity in mind when caring for infants with abnormal thyroid function and refer to otolaryngology and endocrinology as appropriate.
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Citation:Peace MA, Fiorillo CE, Shimy K, Mudd P (2019) Incidental Finding of Lingual Thyroid in an Infant with Hoarseness. J Otolaryng Head Neck Surg 5: 033
Copyright: © 2019 Melissa A Peace, et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.