Lingual thyroid: Endoscopic management with CO2 laser

Lingual Thyroid: With CO2 Laser

Endoscopic

Management

Roberto Puxeddu, MD, Carlo Loris Pelagatti, MD, and Piero Nicolai,

(Editorial Comment: The authors suggest an excellent algorithm for the treatment of lingual thyroid.)

Thyroid ectopia is a rare congenital disease characterized by the presence of thyroid tissue in anatomic sites other than physiological consequent to an abnormal migration of the gland during the embryonic period. The thyroid gland originates around the third to seventh week of development from a proliferation of the pharyngeal intestine epithelium, which invaginates in the underlying mesenchyma between the tuberculum impair and the hypobranchial prominence (foramen caecum). The epithelial invagination goes deep into the mesoderm and descends anteriorly to the pharyngeal intestine by proliferating in its caudal extremity, with the contribution of the fourth and fifth branchial pouchlJ into two lateral lobes. During the migration, the gland remains connected to the floor of the pharyngeal intestine through the thyroglossal duct, which at the end of fetal growth, is completely reabsorbed. Remnants of this diverticulum are responsible for the development of thyroglossal cysts and fistulas, whereas the lack or an aberrant descent of the thyroid rudiment results in lingual, sublingual, prelaryngeal, tracheal, or substernal localization of the gland.3-5 Other rare areas involved in relation to an abnormal deviation from the midline are submandibular,6 carotid, and supraclavicular.7s8 Even pulmonary,g mediastinal,lO~ll and cardiac12-14 localizations have been reported. Several factors, such as genetic, immuno-

From the Department of Surgical Sciences and Organ Transplantations, Section of Otorhinolaryngology, University of Cagliari, Cagliari, Italy; and the Department of Otolaryngology, University of Brescia, Brescia, Italy. Address reprint requests to Roberto Puxeddu, MD, Department of Surgical Sciences and Organ Transplantations, Section of Otorhinolaryngology, University of Caoliari, Via S Freud, 8, 09126 Caoliari, Italy. Copyright 0 1998 by W.B. Saunders Company 0196-0709/98/l 902-0013$8.00/0 136

American

Journal

of Otolatyngology,

MD

logic (ie, maternal antithyroid immunoglobulins),15 toxic, and infectious have been postulated to interfere with the complex organogenesis of the tongue and thyroid, so as to explain the presence of thyroid ectopia. In particular, if the welding of the thyroid rudiment, between lateral and median lingual tubercula, occurs before or during migration of the gland, the thyroid totally or partially does not reach its physiologic site16; too early an appearance of the thyroid bone could also hinder the regular descent of the glandular rudiment. In this report we present a case of lingual thyroid that was resected endoscopically using CO, laser, and review the current knowledge on incidence, diagnosis, and treatment of this disease.

CASE REPORT A 62-year-old woman was admitted to the Department of Otorhinolaryngology of Cagliari University, with a Z-year history of dyspnea attacks, an irritable cough, and a foreign body sensation in the pharynx. Endoscopy showed a reddish, roundish lesion about 2.5 cm in diameter, with a wide base, localized in the base of the tongue and extending to the left glosso-epiglottic vallecula. Ultrasonography revealed the absence of the thyroid gland in the normal position. Computed tomography scanning (Fig l), and magnetic resonance imaging (MRI) (Fig 2) of the neck revealed a nodular and homogeneous mass, with distinct margins, about 2.5 cm in diameter. A marked enhancement after administration of paramagnetic contrast medium was evident on MRI. Analysis of thyroid hormones showed the following values: thyroid stimulating hormone (TSH), 127 QI/mL (normal range, 0.3 to 2.0 t.&J/mL); Ltriiodothyronine (T3), 0.9 ng/dL (normal range, 4.9 to 12.0 ng/dL); L-thyroxine (T4), 20 pg/dL (normal range, 110 to 210 pg/dL). Technetium 99 scintigraphy showed no uptake of the radioactive tracer in the pretracheal area with a moderate sublingual focality. Clinical and instrumental findings led to the hypothesis of a hypofunctioning ectopic lingual

Vol 19, No 2 (March-April),

1998:

pp 136-l

39

ENDOSCOPIC

MANAGEMENT

OF LINGUAL

THYROID

137

nation confirmed the clinical suspicion of lingual thyroid. Tracheotomy was not performed, although the patient’s consent had been obtained in view of a possible profuse hemorrhage. The postoperative course was uneventful, and the patient suffered only a slight odynophagia lasting 15 days. The patient was discharged the fourth day after surgery. At a 16-month follow-up visit, the lingual mucosa appeared normal, and no residual uptake was discovered by thyroid scintigraphy. Substitutive therapy with 100 kg of levothyroxine a day gave complete normalization of the hormonal status.

DISCUSSION Fig 1. Computed tomography tion of contrast medium showing dense, exophytic mass arising tongue.

scan after administraa homogenous, hyperfrom the base of the

thyroid. Suppressive therapy, consisting of 966 pg of levothyroxine a week, obtained a normalization of the hormonal status and a partial remission of symptoms. A year later, the symptomatology had worsened, with more frequent dyspnea attacks and increasing dysphagia. Surgical excision of the mass by an external neck procedure or, if possible, by an endoscopic approach with COZ laser was proposed to the patient, who accepted the endoscopic procedure as first option. After exposure with a bivalve laryngoscope (Fig 3), the ectopic thyroid tissue was removed together with a slight cuff of lingual musculature, using a 3.5 W power and a 460-p,m microspot. The lesion was vascularized mainly from an arterovenous pedicle, which was carefully isolated and cauterized with bipolar forceps. Histological exami-

The clinical occurrence of lingual thyroid has been estimated to vary between 1 of 3,000 and 1 of 10,000 patients.17 However, the incidence is considered to be underestimated because 10% of 200 consecutive routine necropsies was found to have ectopic lingual tissue.rs The disease usually becomes manifest at a mean age of 40.5 years,18 and it is about three to four times more frequent in women than in men.1g-21 The prevalence in women appears to be related to physiological conditions characterized by increased thyroid hormone levels (ie, puberty, menstruation, pregnancy).rs The presence of ectopic thyroid tissue in the tongue may be asymptomatic, constituting an occasional finding. 18~22When there is a decreased production of thyroid hormones, the clinical signs and symptoms of hypothyroidism, which may be already present at birth or may appear from the third to fourth month of life, become evident. In other cases, the functioning ectopic tissue, generally sufficient to satisfy the hormonal needs of the organism under normal conditions, determines a picture of latent hypothyroidism that becomes evident only in situations involving an increased metabolic activity. The deficit of thyroid hormone induces an increase in hematic TSH with secondary hypertrophy of the ectopic thyroid tissue, which therefore becomes clinically manifest, as in our patient. In such a situation, symptomatology may include dysphagia, dysphonia, dyspnea,

Fig 2. MR hyperintense compresses

Tl-weighted lesion of the intrinsic

sagittal sequence the base of the musculature.

showing a tongue that

sensation

of a foreign

body,

and rarely

hemoptysis. Hypertrophy of the ectopic thyroid can compensate the hormonal deficit, so that the patient presents a condition of euthyis rare roidism. In contrast, hyperthyroidism

138

PUXEDDU,

PELAGATTI,

AND

NICOLAI

Fig 3. Endoscopic intrac erative view of the lesion.

and is usually correlated to inflammation or neoplastic transformation of the lesion. The finding of a midline, fungating mass at the base of the tongue suggests the presence of a thyroid ectopy. However, other lesions such as hypertrophy of lymphatic tissue, hemangioma, lymphangioma, fibroma, carcinoma, tumors of the salivary glands, or cysts of the thyroglossal duct should be considered in the differential diagnosis. There is general consensus that biopsy should be avoided because of the risk of an uncontrollable hemorrhage or acute thyrotoxicosis .21,23 Ultrasonography is, in our opinion, an effective tool that indirectly confirms the hypothesis of a lingual thyroid by showing the absence of the gland in the normal position. Thyroid scintigraphy allows a definitive diagnosis and gives important information on the degree of activity of the ectopic tissue. 5,12Computed tomography, even without contrast medium, and MRI, with Tl and T2 weighted images, are extremely useful to correctly define the site and size of the lesion.24-26 MRI, in particular, allows with sagittal images a better delineation of the relationship between the lesion and the intrinsic tongue muscles. Analysis of thyroid hormones generally shows normal to decreased total and free T4 values and elevated levels of TSH and thyroglobulin.5127J8 When the presence of ectopic thyroid tissue is asymptomatic, a wait-and-see policy with periodic follow-up visits is unanimously recommended.2g Pharmacological treatment with

‘P-

levothyroxine is indicated in patients with mild symptoms or when the level of TSH is elevated.2gJ0 Ablation of the thyroid tissue by radioactive iodine 131 is burdened by the possibility of the late occurrence of radioinduced tumors, because the thyroid tissue is often hypoactive and the dose of radioiodine required is generally high.1g,23 Surgery is considered the mainstay in symptomatic forms that fail to be controlled by medical treatment. The transoral approach has been used for anterior lesions, if necessary in association with posterior31 or tota132 midline tongue splitting, which has been proposed to optimize exposure of the lesion and control of the bleeding. The transhyoid approach,17s26 and lateral pharyngotomy21*27 have been reserved for lesions of considerable size or located in the caudal part of the base of the tongue. The use of CO2 laser for the treatment of lingual thyroid was proposed by Maddern et a133 for a 4 x 3 cm lesion of the tongue narrowing the airway in a 3-month-old infant. A transoral excision was performed without complications using silk stay sutures to retract the tongue anteriorly to better visualize the lesion. As in our experience, the use of CO, laser, under microscopic magnification and with laryngoscope exposure, guaranteed a radical resection of a lesion caudally located, with excellent bleeding control, very limited morbidity, and short hospitalization. New laser technology and refinement of the surgical

ENDOSCOPIC

MANAGEMENT

OF LINGUAL

THYROID

technique will probably allow extension of the indications for endoscopic treatment, thereby reducing the need for external approaches. REFERENCES 1. Ohri AK, Ohri SK, Singh MP: Evidence for thyroid development from the fourth branchial pouch. J Laryngol Otol108:71-73,1994 2. Pintar JE: Normal development of the hypothalamicpituitary-thyroid axis, in Braverman LE, Utiger RD: Werner and Ingbar’s, The Thyroid. A Fundamental and Clinical Text (ed 7). Philadelphia, PA, Lippincott-Raven, 1996, pp 6-18 3. Waters ZJ. McCullough K, Thomas NR: Lingual thyroid: Historical data, developmental anatomy and report of a case. Arch Otolaryngol57:60-78, 1953 4. Ferlito A, Giarelli L, Silvestri F: Intratracheal thyroid. J Laryngol Otol 102:95-96,1988 5. Foley TP Jr: Hypothyroidism in infants and children. Congenital hypothyroidism, in Braverman LE, Utiger RD: Werner and Ingbar’s, The Thyroid. A Fundamental and Clinical Text (ed 7). Philadelphia, PA, Lippincott-Raven, __ 1996, ~~988-994 6. Sambola-Cabrer I. Fernandez-Real I-M. Ricart W, et al. Ectopic thyroid tissue presenting as a submandibular mass. Head Neck 18:87-90,1996 7. Larochelle D, Arcand P, Belzile L, et al: Ectopic thyroid tissue: A review of the literature. J Otolaryngol 8:523-530,1979 8. Okstad S: Ectopic thyroid tissue in head and neck. J Otolaryngol 15:52-55, 1986 9. Marchevsky AM: Lung tumors derived from ectopic tissues. Semin Diagn Path01 12:172-184,1995 10. Arriaga MA, Myers EN: Ectopic thyroid in the retroesophageal superior mediastinum. Otolaryngol Head Neck Surg 99:338-340,1988 11. Dominguez-Malagon H, Guerrero-Medrano J, Suster S: Ectopic poorly differentiated (insular) carcinoma of the thyroid. Report of a case presenting as an anterior mediastinal mass. Am J Clin Path01 104:408-412.1995 12. Pollice L, Caruso G: Struma cordis: Ectopic thyroid goitre in the right ventricle. Arch Path01 Lab Med 110:452453,1986 13. Castaldo M, Castaldo F, Gabrielli F, et al: Struma cordis: Thyroide Bctopique intraventriculaire droite. Arch Ma1 Coeur Vaiss 88:275-277,1995 14. Porqueddu M, Antona C, Polvani G, et al: Ectopic thyroid tissue in the ventricular outflow tract: Embryologic implications. Cardiology 86:524-526,1995 15. Van Der Gaag RD, Drexhagre HA, Dessault JH: Role of maternal immunoglobulins blocking TSH induced thy-

139

roid growth in sporadic forms of congenital hypothyroidism. Lancet 1:246-250,1985 16. Tarantino V, Raspino M, Fortini P, et al: L’ectopia linguale totale normofunzionante della tiroide. Minerva Pediatr 36:1021-1025,1984 17. Williams ED, Toyn CE, Harach HR: The ultimobranchial gland and congenital thyroid abnormalities in man. J Path01 158:135-141, 1989 18. Sauk JJ: Ectopic lingual thyroid. J Path01 102:239243,197O 19. Hillness AD, Black JE: Lingual ectopia of the thyroid gland and autotransplantation. Br J Surg 63:924-926, 1976 20. Kansal P, Sakati N, Rifai A, et al: Lingual thyroid: Diagnosis and treatment. Arch Intern Med 147:2046-2048, 1987 21. Alderson DJ, Lannigan FJ: Lingual thyroid presenting after thyroglossal cyst excision. J Laryngol Otol 108: 341-343,1994 22. Baughman RA: Lingual thyroid and lingual thyroglossal tract remnants. Oral Surg 34:781-799,1972 23. Weider DJ, Parker W: Lingual thyroid. Review, case reports, and therapeutics guidelines. Ann Otol Rhino1 Laryngol86:841-848, 1977 24. Willinsky RA, Kassel EE, Cooper PW, et al: Computed tomography of lingual thyroid. J Comput Assist Tomogr 11:182-183,1987 25. Johonson JC, Coleman LL: Magnetic resonance imaging of a lingual thyroid gland. Pediatr Radio1 19:461462,1989 26. Guneri A, Ceryan K, Igci E, et al: Lingual thyroid: the diagnostic value of magnetic resonance imaging. J Laryngol Otol105:493-495,199l 27. Paludetti G, Galli J, Almadori G, et al: Tiroidi ectopiche. Acta Othorhinolaryngol Ital 11:117-133,199l 28. Leger J, Tar A, Schlumburger M, et al: Control of thyroglobulin secretion in patients with ectopic thyroid gland. Pediatr Res 23:266-269, 1988 29. Kansal P, Sakati N, Rifai A, et al: Lingual thyroid diagnosis and treatment. Arch Internal Med 147:20462048,1987 30. Williams JD, Sclafani AP, Slupchinskij 0, et al: Evaluation and management of the lingual thyroid gland. Ann Otol Rhino1 Laryngol105:312-316‘; 1996 ” 31. Ativeh B.S. Abdelnour A, Haddad FF. et al: Lingual thyroid tongue-splitting incision for transoral excisi& J Laryngol Otol109:520-524,1995 32. Kamat MR, Kulkarni JN, Desai PB, et al: Lingual thyroid: A review of 12 cases. Br J Surg 66:537-539,1979 33. Maddern BR, We&haven J, McBraide T: Lingual thyroid in a young infant presenting as a airway obstruction: Report of a case. Int J Pediatr Otorhinolaryngol 16:77-82,1988