추적자기공명영상에서악화된흉추척수내신경집종 : 증례보고및문헌고찰 이소연 1 지원희 1 김선기 1 정찬권 2 박춘근 3 척수내신경집종은드문척수내종양으로추적자기공명영상소견에서악화된증례는보고된바가없다. 우리는신경섬유종이없는환자에서생긴흉추척수내신경집종의초기영상소견과추적자기공명영상을보고하고자한다. 추적자기공명영상에서척수내종양의크기가커지고, 동반된부종의범위가증가하여악성처럼보여도, 척수내종양의감별진단에척수내신경집종을반드시포함하여야하겠다. 서론척수내신경집종 (intramedullary schwannoma) 은척수내종양의약 0.3~1% 를차지하는매우드문종양으로경추 (62%), 흉추 (20%), 요추 (18%) 순으로호발한다 (1, 2). 이러한척수내신경집종에대한이전보고들이있으나, 추적자기공명영상소견에서종양과부종이증가하여악성처럼보였던증례는보고된바가없다. 따라서저자들은척수구멍증 (syringomyelia) 과부종을동반한흉추척수내신경집종이비교적단기간의추적자기공명영상에서악화되었기에이를보고한다. 증례보고 68세남자가하지의감각이상과보행장애가있어본원외래에내원하였다. 환자는내원하기 1년전에 6개월간지속되는하지의감각이상과 2개월간의보행장애로외부병원에서척추자기공명영상 (Fig. 1) 을시행받고흉추 3번 4번사이황색인대비후를진단받아황색인대제거술과감압후궁절제술을시행받았다. 외부병원자기공명영상에서흉추 5번과 7번사이에척수 내병변이있었고, 이병변은 T2 강조영상 (TR/TE 4400/117) 에서결절형의고신호강도로보이고, T1 강조영상 (TR/TE 450/8.6) 에서는대체로척수와비슷한신호강도를보이며조영증강후 T1 강조영상 (TR/TE 450/8.6) 에서는경미한조영증강을보이는종괴였다. 종괴의상방에결절형의병변이있었고이병변은 T2 강조영상에서는고신호강도를보이고조영증강은되지않아, 척수구멍증이거나낭종으로생각되는병변이었다. T2 강조영상에서경미하게종괴주변의고신호강도가있어척수부종을의심할수있었다. 외부병원에서척수종양은양성으로생각하여수술은시행하지않았다. 그러나수술후에감각이상과보행장애가점진적으로더악화되어본원을방문하였다. 내원하였을때감각은흉추 12번이하로양측모두감소되어있었고, 하지의근력은양측고관절, 슬관절, 족관절의신전과, 굽힘모두외부의힘에저항해서운동할만한정도의힘은있었지만정상보다는감소되어있었다. 항문괄약근의기능은유지되어있었다. 다른병원에서자기공명영상을시행한지 1년후본원에서다시척추자기공명영상 (Fig. 2) 을시행하였다. 종괴의크기는 T2 강조영상 (TR/TE 3500/121.5) 과조영증강후 T1 강조영상 (TR/RE 500/13.6) 에서큰변화없었다. T1 강조영상 (TR/RE 500/13.6) 에서는이전외부병원영상과달리대 대한자기공명의과학회지 13:207-212(2009) 1 가톨릭대학교서울성모병원영상의학과 2 가톨릭대학교서울성모병원병리과 3 가톨릭대학교서울성모병원신경외과접수 : 2009 년 9 월 26 일, 수정 : 2009 년 10 월 5 일, 채택 : 2009 년 11 월 4 일통신저자 : 지원희, (137-701) 서울서초구반포동 505, 가톨릭대학교서울성모병원영상의학과 Tel. (02) 2258-6238 Fax. (02) 2258-1457 E-mail: whjee@catholic.ac.kr - 207-
이소연외 체로척수와구분되는저신호강도로보였다. 척수구멍증또는낭종으로생각되는병변과척수부종은큰변화가없었다. 환자는경정맥스테로이드펄스치료를받은후, 하지의감각이상은변화없었지만하지근력이정상으로회복되어퇴원하였다. 퇴원후에하지의감각이상이변화없이지속되어, 본원에서척추자기공명영상을찍은후 6개월경에추적척추자기공명영상 (Fig. 3) 을시행하였다. T2 강조영상 (TR/TE 4000/67) 에서고신호강도로보이는경계가좋은결절형병변은이전영상과비교하여크기가커졌다. T1 강조영상 (TR/TE 750/10) 에 서이병변은저신호강도로보이고이전영상과비교하여서는신호강도가약간높아져서척수와같은신호강도를보이는부분이조금증가하였다. 조영증강후 T1강조영상 (TR/TE 750/10) 에서는조영증강되는병변의두께가더증가하였고, 내부에는조영증강이잘되지않는작은부분이새로이생겼다. 동반된척수부종이흉추 3번에서흉추 8번사이에서보여이전보다침범한범위가증가하였다. 조영증강되는고형성분과동반된부종의범위가커져병변이악화된것으로생각하여, 종괴제거술및흉추 5, 6, 7번감압후궁절제술을시행하였다. 흉 a b c Fig. 1. A 68-year-old man with paresthesia for 6 months. a-d. MR images from outside clinic show severe nodular hyperintense lesion (arrow) within thoracic spinal cord on T2-weighted image (a) at the level between T5 and T7 vertebrae, which is isointense to that of spinal cord in most portions of the mass on T1-weighted image (b) and subtle enhancement on enhanced T1-weighted images (c, d). A small area (arrowhead) with high signal intensity on T2-weighted image (a) and no enhancement on enhanced T1-weighted image (c) is also seen proximal to enhanced mass, suggesting peritumoral cyst or syringomyelia. Subtle peritumoral hyperintense signal is suspicious within thoracic spinal cord on sagittal T2-weighted image (a), suggesting peritumoral edema (curved arrow). Nodular thickening of ligamentum flavum is noted at T3-4 on sagittal images (a-c). d - 208-
추적자기공명영상에서악화된흉추척수내신경집종 추 5번과 7번사이의척수내에있는붉은색의종양이보였고, 이를완전히적출하였다. 현미경검사에서방추세포 (spindle cells) 가밀집하여있는부분 (Antoni A) 과성기게있는곳 (Antoni B) 이보여신경집종으로확진되었다 (Fig. 3e). 후향적으로볼때, 환자의피부에색소침착은없었고다른신경섬유종증의징후들은없었다. 수술후에는하지의근력이모두정상으로회복되었고, 흉추 12번이하의감각이상은변화없었다. 고찰신경집종은척추와척추주변구조물에생기는비교적흔한종양으로, 전체척추종양의약 25-30% 를차지한다 (1). 신경집종은신경집세포 (Schwann cell) 에서기원하므로신경집세포가없는뇌실질이나척수에생기는것은매우드물다 (1). 척수내신경집종은남녀에서빈도의차이가없고, 평균연령은 40대 (12-75세) 이고, 진단당시신경학적증상의기간은평균 a b c Fig. 2. A 68-year-old man with paresthesia after 1 year from initial MR imaging. a-d. Intramedullary lesion (arrow) is again noted with similar extent on T2-weighted image (a) and enhanced T1-weighted image (c) compared with initial MR images (Fig. 1). Sagittal T1-weighted image (b) shows hypointense nodular lesions. A peritumoral cyst or syringomyelia (arrowhead) proximal to enhanced mass and peritumoral edema (curved arrow) are again noted without interval change. Sagittal (c) and axial (d) enhanced T1-weighed images show heterogenous enhancement. All sagittal images show evidence of laminectomy at T3. d - 209-
이소연외 29개월 (6주-12년) 정도이다 (2). 척수내신경집종환자중의 12% 정도에서신경섬유종증이있다 (2). 신경집세포가없는척수내에신경집종이발생하는것에대해 서는발병기전이명확히규명되지않았지만, 배아신경능선 (embryonic neural ridge) 에서기원하여전위된 (ectopic) 신경집세포의종양성변화, 이상 (aberrant) 척수내신경의신경 a b c d e Fig. 3. A 68-year-old man with paresthesia after 1 year and 6 months from initial MR imaging. a-d. Follow-up MR imaging shows interval increase in size of syringomyelia (arrowhead) and intratumoral cyst (arrow) at the level between T5 and T7 vertebae on T2 (a)- and T1 (b)-weighted MR images. Intratumoral cyst is now seen as well-defined low signal intensity on T1 (b)- weighted image without enhancement. The extent of perilesional edema (curved arrow) is much increased on T2 (a)-weighted image. A small area (arrow) with little enhancement is newly visible within the mass on enhanced T1-weighted image (c, d). e. Microphotogram shows the tumor composed of spindle-shaped cells with alternating areas of compact, elongated cells with nuclear palisading and less cellular areas. The tumor cells have abundant eosinophilic fibrillary cytoplasm. Nuclear pleomorphism and mitotic figures are not found (H & E 100). - 210-
추적자기공명영상에서악화된흉추척수내신경집종 Table 1. Summary of Reported Cases of Intramedullary Schwannoma with Syringomyelia and/or Cyst with MRI Sex/Age Spinal Cyst and/or (Reference) Level syringomyelia (level) Edema T1-weighted images T2-weighted images Contrast enhancement M/47 (3) C3-C5 Syringomyelia (T3-T9) No High Low - M/34 (4) T4-T9 Intratumoral cyst Yes Iso Iso Homogenous and syringomyelia F/36 (5) C3-C6 Syringomyelia (C1-T4) No Low Low Homogenous F/17 (6) C1 Intratumoral cyst, syrnogomyelia (Medulla-C6) Yes Low High Ring-like F/51 (7) T5-T7 Syringomyelia (T3-T8) No - - Small area with little-enhancement M/29 (8) C4-C7 Intratumoral cyst and syringomyelia No Low High Ring-like M/68 T5-T7 Intratumoral Yes Low Iso Small area with (This case) cyst and syringomyelia little-enhancement Note. C cervical, F female, L lumbar, M male, T thoracic 집세포, 전척추동맥을따라들어온신경집세포, 후근 (dorsal root) 의신경집세포등에서기원하였을것으로보고있다 (1, 3, 4). 현재까지보고된척수내신경집종의자기공명영상소견은비교적경계가좋은종괴로 T1강조영상에서는척수와같거나낮은신호강도를보이고 T2강조영상에서는고신호강도를보여다른위치에생긴신경집종과큰차이가없었다. 주위의척수에부종을동반할수있고조영증강이잘되며드물게척수구멍증을동반한다 (2). 자기공명영상에서는척수구멍증과낭종모두경계가비교적명확한척수내병변으로, T2강조영상에서는고신호강도로 T1강조영상에서는저신호강도로보인다. 척수내부종역시비슷한신호강도로보여척수구멍증이나낭종과구분이어려울수있다 (2). 척수구멍증또는낭종을동반한척수내신경집종의자기공명영상소견은이전에여섯증례가보고되어있다 (Table 1) (3-8). 종양내낭종을보이는증례는세개였고이중에서두증례에서종양주위낭종과척수의부종을동반하였다 (4, 6, 8). Duong H 등 (4) 이보고한흉추척수내신경집종의증례는시상면 T2강조영상에서몇개의작은결절형의고신호강도병변이척수내에있고, 이범위는조영증강되는종괴보다넓은범위에걸쳐있어서우리의증례와유사하였다. 이증례에서보였던 T2강조영상의고신호강도는수술소견에서종양주위낭종, 척수구멍증으로확진되었다. 지금까지척수내신경집종은 60례이상이보고되어있지만, 추적자기공명영상에서악화된예는보고된적이없었다 (8). 우리증례에서종괴가커지고종괴주위부종이더증가한것은척수내신경집종이양성병변임에도불구하고악성종양처럼오인할수있다는점에서임상적인의의가있다. 우리증례에서는영상소견이악화된것과달리환자의증상과임상소견은변화가없었다. 한편, 본증례에서추적자기공명영상에서새로이보였던, 종양내에조영증강되지않는부분은, Antoni A, B cell 의퇴행성변화이거나종양이자라면서생긴허혈성괴사에의한것으로추정된다 (9). 그러나병리학적소견과는비교분석하지못하였다. 척수내신경집종은비교적흔한척수내종양인별아교세포종 (astrocytoma) 나뇌실막세포종 (ependymoma), 혈관모세포종 (hemangiomblastoma), 전이암과감별이불가능하다. 별아교세포종은소아와젊은성인에서주로발생하고흉추가호발부위이다. 보통 5-6개의척추뼈길이로비교적크기가큰편이며, 경계가좋지않고편심성으로위치하고비균질한조영증강을보이는것이전형적이다. 종양내낭성병변, 종양주변의낭성병변, 척수구멍증을동반할수있다 (10). 뇌실막세포종은경추에호발하고, 경계가비교적좋으며크기는보통 3-4개의척추뼈길이로척수의중심에위치한다. 조영증강은비교적균일하게잘되고, 종양주변에비교적큰낭성병변이잘동반된다 (10). 요약하면, 척수내종양의감별진단에드물지만신경집종을포함하여야하고, 척수내신경집종은척수구멍증이나낭종, 척수부종을동반할수있다. 또한추적기간중에종양이커지고부종이증가할수있다. 참고문헌 1.Ross DA, Edwards MS, Wilson CB. Intramedullary neurilemomas of the spinal cord: report of two cases and review of the lieterature. Neurosurgery 1986;19:458-464 2.Riffaud L, Morandi X, Massengo S, Carsin-Nicol B, Heresbach N, Guegan Y. MRI of intramedullary spinal schwannomas: case report and review of the literature. Neuroradiology 2000;42:275-279 3.Nicoletti GF, Passanisi M, Castana L, Albanese V. Intramedullary spinal neurinoma: case report and review of 46 cases. J Neurosurg Sci 1994;38:187-191 4.Duong H, Tampieri D, Melancon D, Salazar A, Robert F, - 211-
이소연외 Alwatban J. Intramedullary schwannoma. Can Assoc Radiol J 1995;46:179-182 5.Melancia JL, Pimentel JC, Conceiçäo I, Antunes JL. Intramedullary neuroma of the cervical spinal cord: case report. Neurosurgery 1996;39:594-598 6.Kodama Y, Terae S, Hida K, Chu BC, Kaneko K, Miyasaka K. Intramedullary schwannoma of the spinal cord: report of two cases. Neuroradiology 2001;43:567-571 7.Brown KM, Dean A, Sharr MM. Thoracic intramedullary schwannoma. Neuropathol Appl Neurobiol 2002;28:421-424 8.Shenoy SN, Raja A. Cystic cervical intramedullary schwannoma with syringomyelia. Neuro India 2005;53:224-225 9.Parmar H, Patkar D, Gadani S, Shah J. Cystic lumbar nerve sheath tumours: MRI features in five patients. Australas Radiol 2001;45:123-127 10.Bale riaux DL. Spinal cord tumors. Eur Radiol 1999;9:1252-1258. J. Korean Soc. Magn. Reson. Med. 13:207-212(2009) Thoracic Intramedullary Schwannoma Aggravated on Follow-up MRI: Case Report and Review of the Literature So-Yeon Lee 1, Won-Hee Jee 1, Sun Ki Kim 1, Chan-Kwon Jung 2, Chun-Kun Park 3 Departments of 1 Radiology, 2 Pathology, 3 Neurosurgery, Seoul St. Mary s Hospital, The Catholic University of Korea Schwannoma is a rare intramedullary tumor. There has been no reported case about interval aggravation on follow-up MR imaging. We report initial and follow-up MR findings of a thoracic intramedullary schwannoma with syringomyelia and edema in a patient without neurofibromatosis. Intramedullary schwannoma should be included for differential diagnosis of intramedullary tumor even though followup MR imaging shows interval increase in size of the tumor and extent of associated edema to mimic malignancy. Index words : Magnetic resonance (MR) Schwannoma Spinal cord Address reprint requests to : Won-Hee Jee, M.D., Department of Radiology, Seoul St. Mary s Hospital, School of Medicine, The Catholic University of Korea, 505 Banpo-dong, Seocho-gu Seoul 137-701, Korea. Tel. 82-2-2258-6238 Fax. 82-2-2258-1457 E-mail: whjee@catholic.ac.kr - 212-