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[확대내시경. Magnifying endoscopy]

PPT PDF 1.2M (GIE review, 이소정)


1. 정상 위의 확대내시경 소견

위의 정상 및 비정상 확대내시경 소견은 Fukuoka 대학의 Yao 교수가 2013년 Ann Gastroenterol와 2015년 Clin Endosc에 잘 정리한 것을 참고하십시오. microvascular pattern과 microsurface pattern을 한꺼번에 기술하고 있으므로 다소 혼란스럽습니다. 이 둘을 따로 또 같이 생각하면 이해가 쉽습니다.

(1) microvascular architecture (V) : subepitherial capillary network (SECN), CV (collecting venule)
(2) microsurface structure (S): marginal crypt epithelium (MCE), crypt opening (CO)


1) 정상 fundic gland: microvascular pattern은 SECN (subepitheliral capillary network)가 벌집모양을 이루며, microsurface pattern은 marginal crypt epithelium (MCE)에 둘러쌓인 crypt opening (CO)이 SECN 중앙에 위치합니다. Helicobacter 감염이 있거나 위축성 변화가 현저할 때는 이런 정상 소견이 보이지 않게 됩니다.

(a) Schematic diagram of the microvascular architecture and the microsurface structure of the normal gastric fundic gland mucosa corresponding to the surface morphology as visualized by magnifying endoscopy (ME) with narrow-band imaging (NBI). The microvascular architecture is formed by the capillaries and collecting venules. The morphology of each capillary is that of a polygonal closed loop. These loops anastomose repeatedly with each other, forming a regular honeycomb-like subepithelial capillary network pattern. The microsurface structure is made up of the marginal crypt epithelium/white zone (MCE/WZ), and the intervening part in between. The epithelial morphology is visualized as a semitransparent white belt-like structure (the MCE/WZ), showing a circular or oval shape at the center of which lies the crypt opening. (b) ME with NBI of normal fundic gland mucosa. (Muto M. Digest Endosc 2016)

2) 정상 pyloric gland: microvascular pattern은 dark brown colored coil-shaped open loop를 이루며, microsurface pattern은 regular polygonal 또는 curved marginal crypt epithelium pattern을 이룬다.

(a) Schematic diagram of the microvascular architecture and the microsurface structure of the normal gastric pyloric gland mucosa corresponding to the surface morphology as visualized by magnifying endoscopy (ME) with narrow-band imaging (NBI). The microvascular architecture is formed by capillaries and collecting venules, but the latter are rarely observed from the mucosal surface. The morphology of each capillary is that of coil-shaped open loops. The mucosal surface structure is made up of the marginal crypt epithelium/white zone (MCE/WZ) and the intervening parts surrounded by MCE/WZ. The MCE/WZ morphology usually shows polygonal structures but may be curved or linear. (b) ME with NBI of normal pyloric gland mucosa. (Muto M. Digest Endosc 2016)


2. Intestinal metaplasia의 확대내시경 소견

(A) Magnifying endoscopy with narrow-band imaging (M-NBI) findings of light blue crest (LBC) in gastric mucosa with intestinal metaplasia. Fine light blue (light cyan colored) linear reflections are located on the epithelial margins, visualized using M-NBI. (B) M-NBI findings of white opaque substance (WOS) in gastric mucosa with intestinal metaplasia. WOS visualized by reflections/strong scattering of whole projected lights located in the surface epithelium of the intervening part.


3. 위암의 확대내시경 관찰 (3단계 접근법)

1 단계 (정상 소견 익히기) - 위암 내시경 진단을 위해서는 fundic mucosa와 pyloric mucosa의 정상 NBI 확대내시경 소견을 잘 알아야 합니다. Microvascular structure와 microsurface structure가 위치에 따라 다르기 때문입니다.

  1. Microvascular architecture (V) : subepitherial capillary network (SECN), CV (collecting venule)
  2. Microsurface structure (S): marginal crypt epithelium (MCE), crypt opening (CO)

2 단계 (demarcation line 찾기) - 백색광 내시경으로 관찰하다가 의심스러운 함몰부위가 있으면 NBI 확대내시경을 적용합니다. 정상과 비정상의 경계가 보이면 이를 demarcation line이라고 부릅니다. 한 임상연구에 의하면 검진 환자의 20% 정도에서 suspicious lesion이 보여 NBI 확대내시경을 했다고 합니다.

Digest Endosc 2015년 7월호에 WEO Upper GI Cancer Committe

3 단계 (IMVP와 IMSP 확인) - 일단 demarcation line이 있으면 microvascular pattern과 microsurface pattern을 관찰합니다 (VS classification). Irregular microvascular pattern (IMVP)이나 irregular microsurface pattern (IMSP)이 있으면 위암으로 진단할 수 있습니다.


순천향대학교의 최근 논문의 증례입니다.

Korean J Helicobacter Up Gastrointest Res. 2015 Mar;15(1):39-43


Takashi Kanesaka. Endosc Int Open 2015

Takashi Kanesaka. Endosc Int Open 2015

각 소견의 진단 정확도 (Takashi Kanesaka. Endosc Int Open 2015)

Representative cases for each endoscopic microvascular finding. Target lesions indicated with white arrows. a Case 1: dilation and tortuosity were present, but difference in caliber and variation in shape were absent. This lesion was histologically diagnosed as noncancerous. b Case 2: tortuosity was present but dilation, difference in caliber, and variation in shape were absent. This lesion was histologically diagnosed as noncancerous. c Case 3: dilation, difference in caliber and variation in shape were present, but tortuosity was absent. This lesion was histologically diagnosed as cancerous. d Case 4: tortuosity and variation in shape were present but dilation and difference in caliber were absent. This lesion was histologically diagnosed as cancerous. (Takashi Kanesaka. Endosc Int Open 2015)


2016년 1월호 Endoscopy 지에 일본 연구자들이 위암 확대내시경에 대한 상세한 논문을 발표하였습니다 (Shibagaki K. Endoscopy 2016). WLE (white light endoscopy), NBIME (magnification endoscopy with narrow-band imaging), A-NMIME (NBIME with acetic acid enhancement)를 이용하여 macroscopic pattern에 따라 M1/M2/M3, capillary pattern에 따라 C1/C2/C3/C4, surface pattern에 따라 S1/S2/S3으로 나누었고 각각 adenoma/differentiated type EGC/undifferentiated type EGC로 간주하였습니다.

White-light endoscopy (WLE) images illustrating the macroscopic pattern classification of gastric mucosal neoplasms. Type M1, suggestive of adenoma, is a protruding or flat elevated whitish lesion with a roundish edge and a smooth or often nodular surface. Type M2, suggestive of differentiated adenocarcinoma, is an irregularly shaped and depressed, flat, or elevated lesion either with a red color or without discoloration. Type M3, suggestive of undifferentiated adenocarcinoma, is a depressed whitish lesion with or without variously sized reddish nodules.

Magnification endoscopy with narrow-band imaging (NBIME) images illustrating the capillary pattern classification of gastric mucosal neoplasms. Type C1, suggestive of adenoma, has capillaries with a homogenous diameter and distribution, which form round or oval networks (C1-a, network form) or grow within regular mucosal microstructures (C1-b, intra-microstructure form). Type C2, suggestive of differentiated adenocarcinoma, has capillaries with a heterogeneous diameter and distribution, which form a polygonal or incomplete network (C2-a, network form) or grow within irregular mucosal microstructures (C2-b, intra-microstructure form). Type C3, suggestive of undifferentiated adenocarcinoma, has capillaries with a heterogeneous diameter and distribution, which grow in a disordered fashion with an unclear mucosal microstructure. Type C4, which is not related to a specific histologic type, has capillaries that are invisible or obviously decreased in number.

Magnification endoscopy with narrow-band imaging and acetic acid enhancement (A-NBIME) images illustrating the microstructure pattern classification of gastric mucosal neoplasms. Type S1, suggestive of adenoma, has glandular crypts present, with homogeneously sized, shaped and arranged foveolae (S1-a, foveola form) or grooves (S1-b, groove form). Type S2, suggestive of differentiated adenocarcinoma, has glandular crypts present, with heterogeneous foveolae or grooves (S2-a, foveola form; S2-b, groove form). Type S3, suggestive of undifferentiated adenocarcinoma, has absent or severely decreased numbers of glandular crypts.

저자들은 아래 Table 5 결과를 바탕으로 "A-NBIME showed statistically significantly higher diagnostic accuracy for gastric mucosal neoplasms, with good reproducibility, compared with WLE and NBIME, which provided similar lower accuracy."라고 결론짓고 있습니다. 어떻게 해석되어야 할지 고민입니다. Acetic acid를 사용한 확대내시경이 도움이 된다는 것은 인정할 수 밖에 없을 것 같습니다. 하지만 white light endoscopy와 NBI 확대내시경의 차이가 없다는 이번 결과는 기존에 많은 일본 연구자들이 NBI 확대내시경이 진단에 유용하다고 주장했던 것과는 상반되는 것입니다. 저는 이번 연구 결과를 'white light endoscopy도 잘 보면 상당히 좋다'는 방향으로 해석하고 싶습니다. 향후 어떤 방향으로 결론이 모일지 지켜볼 일입니다.


4. 조기위암 ESD 전 lateral margin의 확인

Differentiated-type에서는 white light endoscopy, chromoendoscopy, magnifying NBI 소견으로 범위를 정할 수 있습니다. 그러나 undifferentiated-type에서는 이 모든 것이 크게 도움되지 않아서 병소 주변 조직검사에 의존할 수 밖에 없습니다. 2016년 일본 암연구회병원 연구자들이 undifferentiated-type에서도 어느 정도 도움이 된다는 발표를 하고 있지만... (Horiuchi Y. Gastric Cancer 2016).


5. Undifferentiated-type 조기위암 ESD 전 NBI 확대내시경의 유용성

전통적으로 NBI 확대내시경은 differentiated-type EGC에서 도움이 되고 undifferentiated-type EGC에서는 별로 도움되지 않는 것으로 알려졌습니다. 2016년 일본 암연구회병원 연구자들이 undifferentiated-type EGC에서도 어느 정도 도움이 된다고 보고하였습니다 (Horiuchi Y. Gastric Cancer 2016).


6. 대장 병소에 대한 NBI 및 확대내시경

NBI 확대내시경을 위하여 Sano 등이 capillary pattern classification을 만들었습니다. 그런데 확대내시경이 없는 검사실이 많은 관계로 일반 NBI 내시경을 이용한 NICE 분류법이 나왔습니다.

Depth of invasion을 관찰하는데는 NBI를 이용한 관찰(Capillary pattern 분류나 NICE 분류)보다 chromoendoscopy 후 확대내시경으로 관찰한 pit pattern이 여전히 우월합니다. 따라서 three step strategy라는 것을 이용하여 꼭 필요한 경우는 chromoendoscopy 후 확대내시경을 하도록 권고되었습니다.

색소 분무 후 확대내시경 소견인 pit pattern은 일찍부터 Kudo 분류로 통일되었습니다. 반면, NBI를 이용한 대장내시경 확대내시경 소견에 대해서는 매우 많은 분류법이 난립되어 있었습니다 (Utsumi T. Clin Endosc 2015) . 마침내 2016년 여름 JNET classification이 나오면서 총정리되는 분위기입니다 (Sano Y. Digest Endosc 2016).


[References]

1) NBI magnifying endoscopic classification of colorectal tumors proposed by the Japan NBI Expert Team. Sano Y. Digest Endosc 2016 (PDF)

2) 2017년 5월 20일 내시경기기/스텐트연구회 심포지엄 (그랜드앰배서더호텔)

© 일원내시경교실 바른내시경연구소 이준행. EndoTODAY Endoscopy Learning Center. Lee Jun Haeng.