Colorectal laterally spreading tumors: nonpolypoid lesions ≥10 mm that spread along the wall. Four subtypes — granular (homogeneous / mixed nodular) and nongranular (flat elevated / pseudodepressed). Separate from the Paris classification.
Classification overview
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LST-G · Granular type
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Homogeneous · Even granules
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Mixed nodular · One or more large nodules
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LST-NG · Nongranular type
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Flat elevated · Smooth surface
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Pseudodepressed · Basin-like depression
Granular
LST-G homogeneous
Granular, even granules
GI Calc, Not original, CC BY
Surface
Granular type with granules of similar size and shape
Paris
Usually 0-IIa
Size
Nonpolypoid; diameter at least 10 mm; lateral spread along the wall
Note: Deep SM invasion is low. The 0.5% (CI 0.1–1.0%) is from the Bogie 2018 meta-analysis.
LST-G mixed nodular
Granular + large nodule(s)
GI Calc, Not original, CC BY
Surface
Granular type with one or more large nodules on a bed of granules
Paris
Usually 0-IIa+Is or 0-Is+IIa
Size
Nonpolypoid; diameter at least 10 mm; lateral spread along the wall
Note: Invasion often sits in the large nodule. The 10.5% (CI 5.9–15.1%) is from Bogie 2018.
Nongranular
LST-NG flat elevated
Smooth, no granules
GI Calc, Not original, CC BY
Surface
Nongranular type with a flat, smooth surface and no granules
Paris
Usually 0-IIa
Size
Nonpolypoid; diameter at least 10 mm; lateral spread along the wall
Note: The 4.9% (CI 2.1–7.8%) is from Bogie 2018.
LST-NG pseudodepressed
Basin-like depression
GI Calc, Not original, CC BY
Surface
Nongranular type with a poorly delineated, basin-like depression in the tumor center
Paris
Usually 0-IIa+IIc or 0-IIc+IIa
Size
Nonpolypoid; diameter at least 10 mm; lateral spread along the wall
Note: Highest invasion risk of the four subtypes. The 31.6% (CI 19.8–43.4%) is from Bogie 2018. Consider en-bloc resection.
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Decision support only. Follow current guidelines and local protocols. Classification definitions and terminology follow the original publication language.