Korean Journal of Oral and Maxillofacial Pathology 2015;39(2):507-512 ISSN:1225-1577(Print); 2384-0900 (Online) Available online at http://journal.kaomp.org http://dx.doi.org/10.17779/kaomp.2015.39.2.507 악하선근방에발생한유표피낭증례 조은애산드라 1), 김재영 2), 허종기 2), 전국진 3), 김현실 1) 연세대학교치과대학구강병리학교실 1), 구강악안면외과학교실 2), 구강악안면방사선학교실 3) <Abstract> Epidermoid Cyst Near the Submandibular Region Eunae Cho 1), Jae Young Kim 2), Jong Ki Huh 2), Kug Jin Jeon 3), Hyun Sil Kim 1) Department of Oral Pathology, Oral Cancer Research Institute 1), Department of Oral and Maxillofacial Surgery 2), Department of Oral and Maxillofacial Radiology 3), College of Dentistry, Yonsei University Epidermoid cyst of the oral and maxillofacial region is a soft tissue cyst lined with keratinized stratified squamous epithelium and most commonly arises in the superficial area of the mouth floor. Uncommonly, the epidermoid cyst may arise deeply in the submandibular region and should be differentially diagnosed with cystic salivary gland tumors, developmental cysts and other cystic lesions. We report a rare case of an epidermoid cyst near the submandibular gland, clinically and radiographically mistaken as a salivary gland tumor. Key words:epidermoid Cyst, Submandibular Gland, Salivary Gland Tumor, Fine Needle Aspiration Ⅰ. INTRODUCTION 유표피낭 (epidermoid cyst) 은주로피부에서관찰되는양성의낭으로표피낭 (epidermal cyst), 표피봉입낭 (epidermal inclusion cyst), 각질낭 (keratin cyst) 이라고도불리며, 모공 (hair follicle) 의누두 (infundibulum) 부위에서주로기원하므로누두낭 (infundibular cyst) 이라고도불린다. 피부에발생하는유표피낭은주로외상및외과수술시표피가진피내로함입되어발생하며, 얇은편평상피및각화층으로이장된다. 구강악안면영역에서의유표피낭은피부의유표피낭과 * Correspondence: Hyun Sil Kim. Department of Oral Pathology, College of Dentistry, Yonsei University 50, Yonsei-ro, Seodaemun-gu, Seoul, Korea Tel : +82-2-2228-3033, Fax : +82-2-392-2959 E-mail : khs@yuhs.ac Received: Mar 02, 2015; Revised: Mar 09, 2015; Accepted: Mar 28, 2015 명칭과조직학적소견은동일하나발생원인은다른데, 구강악안면영역에서의유표피낭은발생과정중에첫째와둘째인두굽이의융합이상또는상피의이소성함입에의해발생하는것으로알려져있다. 이러한구강악안면영역의태아피부에서기원한발생학적낭에는, 유표피낭과함께유피낭 (dermoid cyst), 진성낭성기형종 (true cystic teratoma) 이있으며, 유표피낭은나머지두낭이진피성분및다른배엽층의성분을포함하는것과는달리표피성분만으로이장되어있다 1~3). 구강악안면영역의유표피낭은구강저, 혀등의중앙표층부에호발하며크기가클경우에는심부의이설골근이나악설골근및이하부 (submental area) 까지확장되어인두강을좁히고혀를재위치시켜호흡과연하에방해가될수있다 2,4~6). 또한드물게는심부의편측악하선주변부로발생하기도한다 7~10). 본연구에서는좌측악하선에인접하여발생한유표피낭의증례에대해보고하고자한다. 본연구는정부 ( 미래창조과학부 ) 의재원으로한국연구재단의지원을받아수행된연구임 (NRF-2012M3A9B2052523, NRF-2013R1A1A1011652).
Ⅱ. CASE REPORT 2014년 8월, 40세여환이 7개월전부터좌측턱아래부위의종양의크기가점차적으로커진다는주소로타병원에서타액선종양이의심되어강남세브란스병원구강악안면외과에의뢰되어내원하였다. 환자는 2개월전부터병소가두드러지게성장한것이외, 다른임상증상이나기능장애는없었다. 흡연이외특기할만한병력은없었다. 임상검사결과, 좌측악하선주변으로지름약 2.3cm 의파동성을지닌안면종창이관찰되었고, 촉진시에불편감은있었으나경결감은느껴지지않았다. 구강내로는종창이관찰되지않았다. 파노라마촬영시, 타석등의이상소견은관찰되지않았고자기공명영상촬영결과, 좌측악하선이크기가커진상태였고, 악하선전방에경계가명확한 2.0 1.5 2.0cm 의병소가관찰되었다 (Fig. 1 (A)~(B)). 병소는 T1 상에서낮은신호와 T2 상에서높은신호를보여내부가액체로이루어져있음을추측할수있었다 11). 타병원및강남세브란스병원에서각각세침흡인생검을한차례씩시행하였으며, 세침흡인생검결과는관찰가능한세포가관찰되지않아진단에부적합 (material insuffi- ciency) 판정을받았다. 임상적으로, 다형성 선종 (pleomorphic adenoma), 와르틴종양 (Warthin s tumor) 와선양낭성암종 (adenoid cystic carcinoma) 등의타액선종양으로가진단 (tentative diagnosis) 하고병소의절제술을계획하였다. 수술소견에서병소는악하선과인접하지않고전방부에독립적으로존재하여쉽게절제가되었으며경계가명확하였다. 병소를갈라봤을때내부는빈공간을지닌낭성병소의형태였고노란치즈같은끈적끈적한물질이병소내부의가장자리에차있었다 (Fig. 2 (A)~(B)). 조직병리검사결과, 병소는얇은층의중층편평상피로이장된낭이었으며, 낭의내부에는여러층의케라틴이다량함유되어있었다. 일부부위에서는이장상피의부분적파열과함께케라틴, 만성염증세포및케라틴을포식하는이물거대세포들 (foreign body giant cell) 로이루어진가성낭포들이관찰되었는데 (Fig. 3 (A)~ (D)), 이러한부위는세침흡인생검부위로추정되었다. 상피하방은대부분가는섬유성결합조직으로구성되어있었고, 부분적으로림프구를비롯한만성염증세포의침윤이관찰되었으며, 모낭이나피지선, 땀샘등의피부부속기관은관찰되지않았다. 이상의조직병리학적소견을바탕으로유표피낭으로진단하였다. Figure 1. Axial magnetic resonance image reveals a low signal on the T1 weighted image (A), and a high signal on the T2 weighted image (B) of a well circumscribed homogenous mass on the anterior of the left submandibular gland. 508
Figure 2. (A) A well circumscribed mass is located at the inferior of the left platysma and the anterior of the left submandibular gland. (B) When cutting the specimen in to half, thick yellow filling was seen in the inside. Figure 3. (A) Histopathologic examination shows an epithelium lined cyst filled with keratin. (B) High power view shows keratinized stratified squamous epithelium with no other skin appendages. (C) Histopathologic examination shows several pseudocyst formations on the formal fine needle biopsy suspected region, P : pseudocyst. (D) High power examination of pseudocyst reveals foreign body reaction to the keratin. 509
Ⅳ. DISCUSSION 유표피낭이악하선근방에발생할경우에는타액선종양과드물게는악하선에인접하여발생한아가미틈새낭 (branchial cleft cyst) 12), 하마종 (ranula) 또는점액류 (mucocele) 13), 낭림프관종 (cystic hygroma) 14) 등과감별이필요하다. 또한, 타액선종양중낭성변화를보일수있는다형성선종, 저등급점액표피양암종 (low grade mucoepi- dermoid carcinoma), 와르틴종양, 선양낭성암종, 낭선종 (cystadenoma) 및낭선암종 (cystadenocarcinoma) 등과감별이필요하다. 낭성변화를동반한타액선종양은선조직으로구성된종양조직의증식이주로관찰되고, 종양조직의일부가낭성변화를보일수있는데, 이때낭구조는단일낭의형태이기보다는다수의낭구조로관찰된다. 반면유표피낭은단일낭의구조를띤다. 케라틴이관찰된다는점에서타액선종양중다형성선종과유표피낭은공통점을지니지만, 다형성선종에서는케라틴이국소적으로관찰되고주로동심원을이루며층을형성하는케라틴펄 (keratin pearl) 의형태로나타나는것에비해 15), 유표피낭은각화된중층편평상피만으로낭이이장되어있다는점에서감별이가능하다. 이와같이유표피낭과타액선종양의조직병리학적감별점은뚜렷하지만, 임상및방사선학적으로는감별이어려울수있다. 특히타액선종양중피막이잘형성되어있고주변과경계가명확한단일병소로내부낭성변화의비율이높을경우는자기공명영상의 T1상에서낮거나중간정도의신호를보이고 T2상에서높은신호를보여, 진성낭과영상학적으로구분이뚜렷하지않을수있다 11). 본증례에서는병소가방사선상에서악하선의전방부에연결되어있는경계명확한타액선종양으로가진단하였으나, 실제수술시관찰된해부학적위치는악하선과독립적으로위치하고있어별개의병소임을확인할수있었다. 일반적으로구강악안면영역의유표피낭은표층부에호발하여생검이어렵지않으나악하선근방과같이심부에발생하면구강에서접근하는생검이쉽지않아절 제에앞서세침흡인생검을시행하는경우가빈번하다. 낭성병소의세침흡인생검은몇가지문제점이있다. 본증례에서와같이세침흡인생검을반복해서시행하여도병소내부액체만흡인되고진단에필요한세포의양이부적절할수있다. 또한악성여부가밝혀지지않은낭성병소에서세침흡인생검시위음성진단비율은 50% 에서 67% 에이를정도로부정확한편이다 16). 유표피낭이나유피낭과같은각화성낭의세침흡인생검시소량의편평상피를포함하여대부분케라틴성물질이흡인이된다. 각화성낭의케라틴성물질의흡인이부족할경우는아가미틈새낭, 낭성전이편평세포암종도이와유사한소견을보일수있어감별이불가능하다. 마지막으로흡인시낭구조의부분적파열이발생하게되면, 이후조직병리검사에서염증반응과케라틴에대한이물반응이발생하게되는데, 세침흡인생검의과거력이제공되는경우에는이를감안한조직병리진단이가능하지만, 그렇지않을경우는조직병리진단에혼란을줄수있다 17,18). 따라서내부가액체로판단이되는낭성병소의경우는절제에앞서세침흡인생검을시행하기보다는영상학적정보를바탕으로직접적인절제를통한병리진단이더적절하다고판단된다. Ⅴ. REFERENCES 1. Neville BW, Damn DD, Allen CM, Bouquot JE: Oral and maxillofacial pathology. 3rd ed. Philadelphia: Saunders, 2009:32-35. 2. Meyer I: Dermoid cysts (dermoids) of the floor of the mouth. Oral Surg Oral Med Oral Pathol 1955;8:1149-1164. 3. Baliga M, Shenoy N, Mohan R, Naik R: Epidermoid cyst of the floor of the mouth. Natl J Maxillofac Surg 2014;5:79-83. 4. Oginni FO, Oladejo T, Braimah RO, Adenekan AT: Sublingual epidermoid cyst in a neonate. Ann Maxillofac Surg 2014;4:96-98. 510
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