www.ksmrm.org Print ISSN 1226-9751 Case Report 유방과오종의자기공명영상소견 : 2 예보고 남상유 한부경 이선정 이광희 성균관의대삼성서울병원영상의학과 유방의과오종 (hamartoma) 은다양한양의유선조직, 지방그리고섬유결체조직으로이루어진양성종양으로수술로확인되는예는상대적으로드문종양이며자기공명영상에서확인된예는많지않다. 저자들은영상에서진단된유방암이있는여자환자의반대측유방에서우연히발견된증례와만져지는큰종괴로발견되어수술로진단된과오종의자기공명영상소견을보고하고자한다. 서 론 유방의과오종은드문양성종양으로, 다양한정도의지방조직, 섬유조직, 그리고유선조직을포함한다 (1, 2). 유방의과오종에대한유방촬영술과초음파소견에대한보고는많지만자기공명영상소견에대해서는많이알려져있지않다 (3-5). 저자들은우측유방암으로진단받고수술전검사로시행한자기공명영상에서좌측유방에서우연히발견된종괴를가진 44 세여자환자와만져지는큰종괴를주소로내원한 48 세여자환자의과오종을조직학적으로확진하여이에대한자기공명영상소견을보고하고자한다. 증례보고 증례 1 44 세여자환자가우측유방에만져지는종괴를주소로내원하였다. 이학적검사상우측상외측에종괴가촉진되었으며, 타병원에서핵생검을통하여침윤성유방암으로확인되었다. 수술전자기공명영상에서좌측상내측에종괴가우연히발견되었다. 임상적으로만져지는종괴는없었다. 자기공명영상 T1 강조영상에서좌측상내측에약 2 cm 크기의난원형의경계가좋은종괴가보이며주변부는정상 Received; November 1, 2012 Revised; December 18, 2012 Accepted; December 26, 2012 Corresponding author : Boo-Kyung Han, M.D. Department of Radiology, Samsung Medical Center, Sungkyunkwan University School of Medicine, 50 Irwon-dong, Gangnam-gu, Seoul 135-710, Korea. Tel. 82-2-3410-0517, Fax. 82-2-3410-6368 E mail : bkhan@skku.edu 유방조직과같은신호강도로보이고중심부는지방과같은신호강도를보였다. T2 강조영상에서종괴는주변부에고신호강도와중심부에저신호강도의혼합신호강도를보이는국한성종괴로보였으며조영증강시종괴의주변부로결절성조영증강양상을보였고지속형조영증강을보였다 (Fig. 1a-d). 처음초음파에서는못보았으나이차추시 (second-look) 초음파검사에서좌측유방에국한성난원형의고에코성종괴가관찰되었다 (Fig. 1e). 초음파에서보인종괴에대해표지를부착한후시행한유방촬영술에서좌측상외측에약 2 cm 의지방성분을포함한국한성종괴가관찰되었으며, 내부에석회화는없었다 (Fig. 1f). ACR- BIRADS(American College of Radiology-Breast Imaging Reporting and Data System) 범주 3 으로양성추정소견이었으나우측침윤성유방암절제시좌측병변에대하여절제생검을시행받고최종병리소견상과오종으로진단되었다. 증례 2 48 세여자환자가우측유방에만져지는종괴를주소로내원하였다. 이학적검사상만져지는종괴는우측유방거의전체를차지하였고, 종괴에의한통증이나유두분비물, 피부변화는없었다. 양측겨드랑이에만져지는림프절은없었으며, 유방암의가족력이나호르몬치료과거력은없었다. 유방촬영술에서양측유방은치밀유방조직으로우측상외측에약 7 cm 의국한성난원형의등음영 (isodense) 종괴가관찰되었으며, 내부에양성석회화가두개보였다 (Fig. 2a, b). 종괴와인접한유방조직과피부의이상소견은없었으며, 동측겨드랑이에림프절비대는보이지않았다. 초음파검사에서우측유방의만져지는부위인우측상외측전체를차지하는국한성난원형의비교적균일한등에코성종괴가관찰되었다 (Fig. 2c). 종괴의장축은피부표면에평 271
행하였으며후방음향증강이나종괴내석회화, 주변조직의왜곡은보이지않았다. 색도플러 (Doppler) 검사에서종괴내부에혈류의증가는없었다. 자기공명영상소견은 T1 강조영상에서정상유방조직과같은신호강도를보였고지방성분에의한고신호강도는거의관찰되지않았다. T2 강조영상에서는중심부고신호강도, 주변부저신호강도를보이는혼합신호강도의국한성종괴가관찰되었으며지방억제조영증강영상에서종괴의가장자리만약간조영증강되고대부분은조영증강을보이지않았다 (Fig. 2d-f). ACR-BIRADS 범주 3 으로양성추정소견이었으나만져지는종괴로초음파유도하 14 게이지핵생검을시행하였고간질섬유증식 (stromal fibrosis) 으로진단받았다. 절제생검 을시행받고최종병리소견상섬유결체조직, 선조직으로이루어지고지방성분이소량포함된과오종으로진단되었다 (Fig. 2g). 고 찰 유방의과오종은유방종양의 0.1-0.7% 정도를차지하는양성종양이다 (1, 2). 대개증상은없지만지방성분과유선조직의비율에따라부드럽거나단단한종괴로만져질수있으며, 증상이없고정상유방조직과비슷할경우에는크기가커진후에야발견되기도한다. 주로 35 세이상의여성 a b c d e f Fig. 1. A 44-year-old woman with hamartoma of the left breast. a. Axial T1-weighted spin echo MRI (TR/TE, 400/7) shows a 2 cm, oval shaped, circumscribed mass with central high signal intensity and peripheral iso signal intensity in left upper inner quadrant (arrow). b. Axial fat - suppressed fast spin echo T2-weighted MRI (TR/TE, 5000/70) shows a mass with central iso signal intensity, which was regarded as fat component and peripheral high signal intensity (arrow). c. Sagittal dynamic contrast-enhanced fat-suppressed T1-weighted image MRI shows mild peripheral nodular enhancement of the mass (arrows). d. The time- intensity curve obtained from the site of nodular enhancement during dynamic contrast enhanced MRI shows the presence of a gradual enhancement pattern. e. Second-look ultrasonogrpahy shows an oval shaped, circumscribed, hyperechoic mass in the left upper inner quadrant (arrows). f. Mediolateral mammogram shows a 2 cm, oval shaped, well-defined mass with internal fat density (arrows). 272
유방과오종의자기공명영상소견 남상유외 에서발견되며선별유방촬영술에서우연히발견되는경우가가장흔하다. 절제술후재발하지않고악성변성을하지않으며유방암발생의상대적인위험도도증가하지않는다. 조직학적으로유선조직과결체조직, 지방조직이섞여있는형태이며주를이루는성분에따라섬유선지방종 (fibroadenolipomas), 지방섬유선종 (lipofibroadeno- a b c d e f Fig. 2. A 48-year-old woman with hamartoma of the right breast. a, b. Craniocaudal and mediolateral mammograms of her right breast show a 7cm sized, oval shaped, circumscribed, isodense mass at palpable site of the right breast (arrows). c. Ultrasonography shows an oval shaped, circumscribed, heterogeneous and isoechoic mass (arrows). d. Axial T1-weighted spin echo MRI (TR/TE, 660/8) shows an oval shape, circumscribed mass with iso signal intensity (arrows). e. Axial fat - suppressed fast spin echo T2-weighted MRI (TR/TE, 5,500/70) shows a mass with mixed signal intensity (arrows). F. Sagittal dynamic contrast-enhanced fat-suppressed T1-weighted image MRI shows no enhancement except a little peripheral enhancement (arrow). g. Photomicrograph shows several small clusters of adipocytes within a densely fibrotic stroma (adipocyte (black arrows), glandular tissue (white arrows), fibrous tissue (black arrowheads), haematoxylin and eosin stained; original magnification, 100). g 273
mas), 그리고선지방종 (adenolipomas) 으로불리기도한다. 과오종의구성성분이정상유방조직과매우유사하고때로는서로섞여있어병리학적진단이어려워지기도한다. 따라서정확한진단을위해서는임상적그리고영상의학적소견을참고하는것이중요하다. 과오종의유방촬영술소견은특징적으로 유방내유방 (breast within a breast) 소견을보이며경계가매우좋은종괴로보인다 (6, 7). 모양은구형또는난원형이며얇은고음영의가성피막으로둘러싸여있다. 지방성분과섬유조직, 그리고유선조직의혼합정도에따라혼합성밀도로관찰되며내부에유선과결체조직에의한고음영부위와지방조직에의한저음영부위가번갈아있는 잘린소시지단면 (slice of salami) 모양을보인다. 유방촬영술에서이와같은특징적인모습을보이면 BI-RADS 범주 2 로분류되며유방초음파나조직검사를하지않고도과오종을진단할수있다. 그러나이러한특징적인소견들은종괴가큰경우에볼수있고전체과오종의 10-60% 에서만관찰할수있다 (8). 유방초음파에서과오종은고에코의섬유성분과다양한비율의등에코의지방또는선성분이섞여서비균질한혼합성에코로보이며때로는낭성변화를동반하기도한다 (9, 10). 경계가좋은구형혹은난원형의종괴로보이며종괴가주변정상조직을밀어서생기는가성피막이보일수도있다. 또한종괴내부의지방성분때문에부드럽게잘눌려압박성 (compressibility) 이좋다. 지방성분으로만이루어져있을때에는지방종과구분하기어려운등에코의종괴로보이고, 선성분이주를이룰때에는섬유선종과비슷한모양을보인다. 그러나 Adler 등에의하면과오종의초음파소견이매우다양하기때문에과오종의진단에있어초음파의역할은미미하다고도하였다 (3). 과오종의자기공명영상소견을많은예로보고한연구는흔치않으며 Erdem 등이 8 예 (11), Tse 등이 4 예 (9), Kievit 등 (4) 과 Testempassi 등 (5) 이각각 1 예씩을보고하였다. 과오종은내부에지방성분을포함하는경계가좋은난원형의종괴로불균일한신호강도를보인다. 역동적조영증강자기공명영상에서는지속형조영증강을보여양성종양의특징을보이며내부는불균일한조영증강을보인다. 확산강조영상에서과오종의현성확산계수값 (Apparent Diffusion Coefficient value) 은정상유방조직과유사하며섬유조직이주성분인과오종보다는지방과유선조직이주를이루는경우에더높게나타난다 (12). 본증례는유방촬영술에서국한성난원형의등음영혹은지방성분을포함한혼합성음영의종괴로관찰되었으며, 내부에양성석회화가있거나혹은없었다. 초음파검사에서는국한성난원형의불균일한동에코성혹은고에코성종괴로보였다. 자기공명영상에서종괴는 T2 강조영상에서불균질 한혼합신호강도, 역동적조영증강에서는거의조영증강되지않거나부분적으로만지속형조영증강을보여양성종양을시사하는소견이었다. 본증례 1 과같이 T1 강조영상에서지방성분에의한고신호강도가보일수있는데증례 2 에서는지방덩어리 (lump of fat) 에의한고신호강도가보이지않았으나현미경소견에서지방성분이포함되어있어과오종으로진단할수있었다. 본증례에서는유방암으로진단된환자의수술전자기공명영상에서우연히발견된예와, 만져지는큰종괴로내원하여조직검사로간질섬유증식으로진단받았으나정확한수술방향을정하기위하여자기공명영상을시행하고수술을하여최종적으로과오종으로진단된예의자기공명영상소견을보여주었다. 과오종의유방촬영술과초음파소견은영상의학과의사에게비교적친숙하지만자기공명영상소견은그렇지않은경우가있으므로과오종의자기공명영상소견을잘숙지한다면불필요한검사나수술을피할수있을것으로생각된다. 참고문헌 1. Fisher CJ, Hanby AM, Robinson L, Millis RR. Mammary hamartoma--a review of 35 cases. Histopathology 1992;20:99-106 2. Charpin C, Mathoulin MP, Andrac L, et al. Reappraisal of breast hamartomas. A morphological study of 41 cases. Pathol Res Pract 1994;190:362-371. 3. Adler DD, Jeffries DO, Helvie MA. Sonographic features of breast hamartomas. J Ultrasound Med 1990;9:85-90 4. Kievit HC, Sikkenk AC, Thelissen GR, Merchant TE. Magnetic resonance image appearance of hamartoma of the breast. Magn Reson Imaging 1993;11:293-298 5. Testempassi E, Ishi C, Yamada T, Fukuda K, Tada S, Nikaido T. Case report: breast hamartoma: MR findings. Radiat Med 1995;13:187-189 6. Hessler C, Schnyder P, Ozzello L. Hamartoma of the breast: diagnostic observation of 16 cases. Radiology 1978;126:95-98 7. Paraskevopoulos JA, Hosking SW, Stephenson T. Breast within a breast: a review of breast hamartomas. Br J Clin Pract 1990;44:30-32 8. Pui MH, Movson IJ. Fatty tissue breast lesions. Clin Imaging 2003;27:150-155 9. Tse GM, Law BK, Ma TK, et al. Hamartoma of the breast: a clinicopathological review. J Clin Pathol 2002;55:951-954 10. Chao TC, Chao HH, Chen MF. Sonographic features of breast hamartomas. J Ultrasound Med 2007;26:447-452; quiz 453 11.Erdem G, Karakas HM, Isik B, Firat AK. Advanced MRI findings in patients with breast hamartomas. Diagn Interv Radiol 2011;17:33-37 12. Kinoshita T, Yashiro N, Ihara N, Funatu H, Fukuma E, Narita M. Diffusion-weighted half-fourier single-shot turbo spin echo imaging in breast tumors: differentiation of invasive ductal carcinoma from fibroadenoma. J Comput Assist Tomogr 2002;26:1042-1046 274
유방과오종의자기공명영상소견 남상유외 MR Findings of Hamartoma of the Breast: A Report of Two Cases Sang Yu Nam, Boo-Kyung Han, Sunjung Lee, Kwanghwi Lee Department of Radiology, Samsung Medical Center, Sungkyunkwan University School of Medicine Breast hamartoma is a relatively rare pathology, composed of various amount of mammary glandular, fatty and fibrous tissue. Here, we report MR findings of two cases of hamartomas; one of them was incidentally found in her left breast during preoperative MRI in a woman with right breast cancer, and the other was presented as a large palpable mass. Both of them were confirmed by surgical excision. Breast hamartoma shows a well-defined mass with mixed signal intensity on T2-weighted image MRI and a little or focal enhancement on contrastenhanced MRI. Index words : Breast neoplasms Hamartoma Magnetic resonance imaging (MRI) Address reprint requests to: Boo-Kyung Han, M.D., Department of Radiology, Samsung Medical Center, Sungkyunkwan University School of Medicine, 50 Irwon-dong, Gangnam-gu, Seoul 135-710, Korea. Tel. 82-2-3410-0517 Fax. 82-2-3410-6368 E-mail: bkhan@skku.edu 275