Thyroglossal tract remnants with cyst in an adult cadaver

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맨뜨애 PI?aLptl!edtine-a?d민eScience V01감핀，켄→0，"HJune!

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2013

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Thyroglossal σact remnants with a cyst in an adult cadaver

Sung H)'un Kim " Young Hee Maeng' ，Sang PiI Yoon' ，' lMedicalcourse‘

’

Departmen101Palhology，3Department01Ar녕lomy，SChool01Medicine，

Jeju NationalUniversity，Jeiu-Do，Republic01Korea

(ReceivedApril 18. 2013: Revised April 25，2013: Accept.edMay 2. 2013)

Abstract

]

이though 1hyr09lossal tract rem쩌nts are nol uncommon in adulls，iI is s1illimpartant due 10 the carcinomatous involvemen1

We lound a case 01 Ihyroglossal tract remnanls with a cyst lormation in a 37-year-old Korean male cadaver during a routine dissection course，whose cause 01 death was rectal carcinoma. A left-deviated Ihyroglossal duct cysl was located lhyrohyoid

level and 1hyroglossal tracl remnants connecled below and above，behind 1he hyoid bone，the Cys1. In addilion，we examined the POssible invotvement 01 carcinoma in Ihyroglossal duct cysl his10pa1hologically，but found il a simple cysl containing respìratory epithelium and thyroid follicles. These results indicated Iha1 clinìcians should keep in mind the possibility of carìnomalous change wilh thyr0910ssal ducl cysl in ad비t patie미s over fourth decades ，although 1he prevalence is very low. (J Med Ufe SCi 2013;10(1):36-38)

Key Words : AduJt，Embryology. Neoplasia. 까1YJ'Oglossalduct앙st

Correspondence to Dr.Sang PiIYoon，

Department이Anatomy，SChool이Med디ne，Jeju NationalUniversJty，

102 Jejudaehakno，Jeju-Si，Jeiu-뀐。690-756，Republicof Korea

E-mai1:[email protected]

Clinicians frequently encounter adult patients witb a neck mass of various causes such as congeni1al/developmental anom외ies，infectionlinflanunation‘σ--aurna，toxic，endocrine， neoplasm 뻐d sYStemic diseasesl). These masses may be

confused with thyroglossal tract remnants due to their location and charact.er". Thyroglossal duct cyst (1'GDC) is the most common congenital neck anomalyll 、이lich usu811y

presents 8S a midline cyStic mass close

ω

야lC hyoid bone

In general ，the signs related to the presence of 1hyroglossal In~ct remnan1s that appaar during childhood can be treated surgically. However，the tract may lie donnant for year응 or decades until some stimuli lead to cyStic dilatation

As a res버

ι

1'GDC can be obseπed about 7% of the .d비t

populationSl or cadave~f. We herein report a rare case of 1'GDC in뻐 adult cadaver，since the vast m예。ril;y of 1'GDCs

were diagnosed before tl1e age of 30~

During a routine dissection at JEÜu National University

r

Introduction

Case Report

그

Medical School in 2012. a case of 1'GDC was obseπ-ed in a 37-year-old Korean male cadaver，whose cause of deatb was ‘rec떠1 carcinorna'’The protocol for 1he current report

did not include any specific lssue that needed to be approved by the ethics comrnittee of 0따 institution 뻐d it confonned

to the provisions of the Declaration of Helsinki in 1995 Gross dissection was perfonned in ilie customary fashion D니ring dissection on the neck we found Ü1yroglossal duct

remnants，which had off-rnidline componen1s embedded in tbe stemohyoid and slerno싱1YJ'Oidmuscles. 1'GDC(]이g. lA)

was located in front of the thyroid cartilage. left-sided thYI히1YOidor irûrahydoid level (be뼈een the hyoid bone and the

thyroid cartilage)까JYI"O명。$외1ract remnants e쳐""ded up\쩌떠

from the cyslic structure to the hyoid with • few branches and a small양st (0.4xO.2cm).and did not have

∞

nnection with the

thyroid멍and에'terta뼈ing below the 1'GDC

The excised TGDC was uniloculated and measured 2.Oxl.OxO.6cm.Some skeletal muscle was atiached tó the outer surface. On section. tbe cystic cavity contained li앙，t brownish turbid fluid. Microscopic examination (Fig. lB) revealed a complex cystic structure Iined by respiratory epiLhelial cells (Fig. 1Bl). Also not.ed were some thyI'Oid fol1icles in the surrounding fibromuscular tissue (Fig. lB2) Each follic1ewas filled with condensed colloid mate끼.1 and

lined by a single layer of beni밍1 cuboidal epithe1ium η'ere was no evidence of carcinomatous change or metastatic adenocarcinoma

Thyroglossal tract remnants with cyst in an adull cadaver ..•.-;

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f

ι.

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Figure 1.. Fhotograph

ω

。

f the tJWO영OSSaItroct romnants (ærows) with a cyst fonnation(，잃따iskl. Micrograph.

，

(3)허10Wing8complex

cystic해uclllre Iirεd by

""핑

iratmy epithelium030 and some iIwoid folliclesinlhe SUJT()Ul얘ing엉ìtiæue (32). SCM. stemocleidomastoid mu영e: SH. stemohyoidmuscle π1. tJwohyoidmu잉e

Discussion

Thyroglossal tract remnants may be found of diverse clinical presentations. since it c뻐 be situated anywhere

along the developmental tract as traced in a cadaveric stu여끼 π1e majori~ of TGDCs occur in c10se proximity to the hyoid bone，but infrahyoid，left-de씨ated TGDC is more

frequent in aduJts8.71just like this case. We found the TGDC with thyroglossal tract 1엉mnants below and above with a small

cyst be

“

nd the hyoid bone in an ad비t cadaver. In addition.

we examined the possible involvement of carcinoma histopat1lologica11y，but found it a simple cyst

까1e Sistru따‘s procedure is the treatment of choice for removal of the TGDCSlin continuity with the mid-portion of the hyoid bone and with a core of tissue towards the foramen cecum. Successful treatment requires an understanding of the embryology and anatorny of the tongue，the thyroid gland and the hyoid bone" 깨e primitive thyroid gland develops mainly from an invagination of the endodermal cel1s of the ventral noor of the primitive pharynx just between the copula 밍1d the tuberculum impar

During its downward movement in the midline，anterior to the hyoid bone，the gland leaves behind an epitheli외Ù'ac~

known as thyr。밍。ss외 tract，끼，e thyro잉。SSaJ σact usually

atrophies and disappears between the 5th and 10th

gestational week'

‘

51 As aconsequence，TGDC can be located at any site along the pathway of descent of the thyroid anlage. and the failure of this tract ω c10se predisposes the formaüon of a cyse.s'l.Usually the ve며cal location of TGDCs

is described as Iingual. suprahyoid ，thyrohyoid or suprasteπal"

An important consideration is that approximately 1% of aduJt TGDC contain carcinoma foci5.1.1'l.since 809"0 of neck masses are associated with a neoplastic process for patients over 40 yearsil，Neoplastic lesions，beni밍1 or malignant. in

TGDCs are unusual8l，but present most common1y in the fourth deeade of life10l.TGDC carcinoma is generally either of thyroid or squamous cell ori밍n: papillary carcinoma (8α)&)

is the most common type，fol1owed by mixed papillary follicular carcinoma (8%) and squamous cel1 carcinoma (6%)" π\ere is an agreement that the minimum treatment for a TGDC carcinoma is a Sistrunk's procedurel이 Because

the clinical presentation of TGDC neoplasia is very similar to that of a TGDC，it is usually discovered incidentaJly during pathologîcal examination of the TGDC specimen. ln this con\ext，we examined the TGDC histopathologically and found it had nothing to do with TGDC carcinoma or metastasis from rectal carcinoma which is the cause of death in this cadaver，Nevertheless‘TGDC sho비dbeap 강t

。

f the clinician’s differential diagnosis when presented with

‘ 37

Sung Hyun Kim.YoungHec Maeng..ßang Pil Yoon a neck mass in adult patients

In condusion. we report untreated TGDC in a Korean male cadaver regardless of carcinomatous involvement. But. c1inicians should remember whether a nonnal thyroid gland exists in its origin외 loca니。n before operation. since TGDC

may rarely contain the only functional thyroid tissue in adullsll. In addition ‘clinicians should check the histopathological results postoperatively ，since c1inical presentation of TGDC carcinoma is often similar -to a benign cyst띠

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