Simple magnifying (M-NBI) diagnostic algorithm for early gastric cancer. After a suspicious lesion on white-light imaging, decide by the demarcation line (DL), then irregular microvascular (IMVP) and/or irregular microsurface (IMSP) patterns within the DL. Separate from colorectal JNET / NICE. Stomach only.
Classification overview
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Algorithm
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Suspicious lesion · Identify on WLI
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Demarcation line (DL) · First step
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Diagnosis
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Non-cancer
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Irregular MV and/or MS within DL
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VS classification · microvascular
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Regular MV · Regular
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Irregular MV · Irregular
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Absent MV · Absent
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VS classification · microsurface
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Regular MS · Regular
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Irregular MS · Irregular
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Absent MS · Absent
Algorithm
Tap a choice to highlight the path and see the next step. The diagnosis appears after every step is chosen.
Algorithm
Is a demarcation line (DL) present?
A border between the lesion and background mucosa, seen as an abrupt change in MV and/or MS. If absent, diagnose non-cancer. If present, look inside the DL next.
Diagnosis
Select every item to see the result
Suspicious lesion
Identify on WLI
Color
Whitish or reddish color change; mucosal discoloration (erythema or pallor).
Morphology
Elevated, flat, or depressed change; tapered or interrupted mucosal folds.
Other clues
Spontaneous bleeding, localized opacity of the mucosa, or loss of mucosal glossiness.
Note: Look for subtle color or morphological change on white-light imaging. Stomach only. Separate from colorectal JNET / NICE.
Demarcation line (DL)
First step
Definition
A border between the lesion and non-lesion areas, discernible through an abrupt change in MV and/or MS patterns.
Order
Identification of a DL is the first step in distinguishing EGC from a non-cancerous lesion.
Note: If the demarcation line is absent, diagnose non-cancer. If present, evaluate MV and MS separately within the DL.
Non-cancer
DL absent
If a DL is absent, the diagnosis of a benign lesion may be made.
Regular MV and MS within DL
Inside the demarcation line, there are regular microvascular and regular microsurface patterns. Because neither an irregular microvascular nor irregular microsurface pattern is present, this lesion can be diagnosed as non-cancer.
Irregular MV and/or MS within DL
Criteria
(i) an irregular MV pattern with a DL; and/or (ii) an irregular MS pattern with a DL.
Diagnosis
If irregular MV and/or MS patterns are present within the demarcation line, the diagnosis of EGC can be made.
Note: The original paper reports that 97% of EGC cases fit these criteria. Diagnostic yield for undifferentiated (diffuse-type) EGC was unclear. Contact bleeding or mucus can prevent a clear image.
Mucosal capillaries have a uniform shape that can be closed-looped (polygonal) or open-looped with a homogeneous morphology, a symmetrical distribution, and a regular arrangement.
The vessels are closed-looped (polygonal), open-looped, tortuous, branched, or bizarrely shaped, have asymmetrical distribution and irregular arrangements.
Morphology
Cancer-specific morphology of irregular microvessels has been described as dilation, heterogeneity in shape, abrupt caliber alteration, and tortuousness.
Note: A later subclassification (fine-network for differentiated, corkscrew for poorly differentiated) is not a MESDA-G branch.
If a MV pattern is not fully visualized because of the presence of a white opaque substance (WOS) which obscures subepithelial microvessels, the MV pattern is described as absent.
WOS
In cases in which the WOS is observed, rather than assessing the MVP, morphological analysis of the WOS could be an alternative marker of MS pattern.
Note: When white opaque substance (WOS) hides vessels, use WOS morphology as an alternative marker of the microsurface pattern.
The MCE/WZ is an irregular linear, curved, oval, circular, or villous structure with heterogeneous morphology, asymmetrical distribution, and irregular arrangement.
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Decision support only. Follow current guidelines and local protocols. Classification definitions and terminology follow the original publication language.