Lingual Thyroid Ectopia: Diagnostic SPECT/CT Imaging and Radioactive Iodine Treatment

BACKGROUND

Lingual thyroid is a rare abnormality of thyroid development that is usually treated conservatively with levothyroxine replacement. Rarely, it becomes large enough to cause obstructive symptoms in the oral cavity, requiring definitive treatment.

PATIENT FINDINGS

This study reports on three patients with lingual thyroid treated with radioactive iodine-131 ((131)I) with successful radioablation of their ectopic thyroid tissues. Measurement of 24-hour radioactive iodine uptake within thyroidal tissues and hybrid single-photon emission computed tomography/computed tomography imaging using either iodine-123 or technetium-99m pertechnetate scans were performed in all patients demonstrating the location and size of lingual thyroid and absence of an orthotopic thyroid gland.

SUMMARY

The aim of this study was to describe nonsurgical management of obstructive lingual thyroid tissue with (131)I therapy for lingual thyroid radioablation. Patients were prepared with a low-iodine diet and levothyroxine withdrawal prior to radioablation for optimizing (131)I uptake in ectopic thyroid tissues. Hybrid single-photon emission computed tomography/computed tomography measurement of anatomic size of lingual thyroid tissue and radioactive iodine uptake guided the selection of therapeutic doses, resulting in administration of 10.7, 17.5, and 15.4 mCi of (131)I, respectively. There were no post-therapy complications, and clinical follow-up demonstrated resolution of obstructive oropharyngeal symptoms.

CONCLUSIONS

Ectopic lingual thyroid tissue is rarely associated with obstructive oropharyngeal symptoms due to progressive enlargement. Radioiodine therapy with (131)I is an effective treatment modality for ablation of ectopic thyroid tissue as an alternative to surgery.

Normal variations of oral anatomy and common oral soft tissue lesions: evaluation and management

Examination of the oral cavity can provide significant diagnostic information regarding the general health of the patient. The oral cavity is affected by a multitude of pathologic conditions of variable cause and significance; however, there are numerous normal variations of oral soft tissue structures that may resemble a pathologic state. Understanding these variations assists practitioners to discriminate between normal versus abnormal findings and determine the appropriate course of management, if necessary.

Lingual thyroid in adults: management algorithm based on swallowing outcomes

OBJECTIVE

To review the presentation, workup, and functional outcomes of adult patients diagnosed with lingual thyroid treated by transoral subtotal excision. These results were then used to formulate a management algorithm.

DESIGN

Retrospective chart review (2001-2008).

SETTING

Tertiary care academic hospital.

PATIENTS

All patients diagnosed with a lingual thyroid as an adult were identified in the University of Alberta's head and neck mass database. Charts were reviewed for initial presentation, diagnostic methods, radiographic findings, and treatment and follow-up results.

INTERVENTION

Transoral subtotal excision of lingual thyroid tissue.

MAIN OUTCOME MEASURE

Postoperative swallowing function as measured by pharyngeal residue and aspiration on videofluoroscopic swallowing studies.

RESULTS

Five patients with lingual thyroids meeting the study criteria were identified. All were females aged 29 to 58 years (mean 44 years). Presentations ranged from asymptomatic to acute airway obstruction. Diagnosis was made with flexible nasopharyngoscopy, thyroid scintigraphy, and computed tomography. All patients underwent transoral subtotal excision of their thyroids with either a CO2 laser or electrocautery. Two patients complained of residual symptoms and received adjunctive 131I, which led to symptom resolution. Pathologic evaluation revealed benign thyroid tissue. Swallowing function remained efficacious and safe in all patients, as shown by a lack of aspiration and low pharyngeal residue scores. These results were used to propose a management algorithm for the spectrum of adult-diagnosed lingual thyroid presentations.

CONCLUSIONS

Transoral subtotal excision of lingual thyroid glands provides adequate resection of the lesion with good postoperative swallowing function. When appropriate, this is advocated as the treatment modality of choice.

Follicular variant of papillary carcinoma arising from lingual thyroid

Malignant transformation of ectopic lingual thyroid tissue is an uncommon event; only 43 cases have been reported in the literature. Only 10 of these cases were papillary carcinomas, in contrast to normal thyroid gland neoplasms, of which papillary tumors form the predominant group. We present a case of a follicular variant of papillary carcinoma originating from the lingual thyroid, along with a review of the literature. Our patient was treated with surgical excision followed by (131)I therapy. To date, only 2 other cases of a follicular variant of lingual thyroid tumor have been reported.

Lingual thyroid

Lingual thyroid gland is a rare clinical entity caused by failure of the gland's anlage to descend early in the course of embryogenesis. It may present with symptoms of dysphagia, upper airway obstruction, or even hemorrhage anytime from infancy through adulthood. Treatment of this disorder includes the use of exogenous thyroid hormone to correct the hypothyroidism and to induce shrinkage of the gland. When symptoms of obstruction or bleeding appear, ablative therapy by means of surgery or radioiodine is warranted. We report our experience with lingual thyroid gland and discuss elements of the diagnostic and therapeutic evaluation, with emphasis on the clinical findings, laboratory tests, and radiographic imaging studies.

[Lingual thyroid]

Lingual thyroid is a rare congenital malformation that occurs more frequently in the female population. It occurs because of the error in transcriptional factors, the key for the normal differentiation of thyrocyte, so the thyroid gland tissue does not descend normally down the thyroglossal duct to the final position in the neck. Due to that, it can entirely or partially remain at the base of the tongue. This is the most frequent localization of the ectopic tissue while it can remain in the sublingual, suprahyoid and infrahyoid area as well. This disease can be diagnosed in the asymptomatic phase, as well as in the phase of compensatory and manifest hypothyroidism. In the ectopic thyroid gland, all diseases of the thyroid gland can occur as in the usual localization in the neck. The authors show a 6-year old patient, who had a routine medical examination for the inflamed throat, during which a vascular tumefaction was discovered at the base of the tongue. A cyst at the base of the tongue was suspected, but additional examination showed that it was an ectopic thyroid tissue marked as a lingual thyroid gland. Diagnosis of this disease starts with the laboratory analysis of the thyroid status. The next step involves scintigraphy of the thyroid gland with technetium-pertechnetate (99mTc) or radioactive iodine (123I). The therapy of the compensatory hypothyroidism is suppressive therapy with levothyroxine and in the manifest hypothyroidism it is hormone substitution therapy with levothyroxine. Although there are recommended age-related daily doses, they should not be accepted as final, but rather prescribed according to the individual thyroid status.

[Lingual thyroid--case report: a woman with a tumor at the base of the tongue]

We report a case of lingual thyroid. A woman presented with a few years history of mild dysphagia, cough and uncomfortable breathing when going to sleep at night. Laryngostroboscopy showed a mass lesion at the base of the tongue. A CT scan and thyroid scanning revealed a bilobar mass of thyroid tissue, compatible with a lingual thyroid. No thyroid gland was found at its usual location. The woman was euthyroid and since her symptoms were mild she was treated with thyroxin and observation. Lingual thyroid is a rare phenomenon caused by abnormal migration of thyroid cells during the first weeks of fetal life. Females are affected more often than males and although this condition is often asymptomatic, symptoms can occur, most often during puberty, pregnancy and menopause. On examination a mass is noted at the base of the tongue and the diagnosis is then confirmed with CT/MRI and thyroid scanning. Treatment can vary from observation to thyroxin medication, radioactive iodine and complicated surgical intervention, depending on the symptoms and the overall health of the patient.

Lingual thyroid as a cause of snoring and sleep apnea

Lingual thyroid is a rare developmental abnormality. We describe a case of lingual thyroid in a 28 years old female who presented with symptoms of heroic snoring and obstructive sleep apnea. She was treated with surgery and was advised a life long thyroid hormone replacement therapy.