Macroscopic types I–IV of elevated gastric lesions by the shape of the base. Not a histologic classification. Mapping onto Paris 0-Ip / 0-Is / 0-IIa is approximate.
Classification overview
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Yamada
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Type I · Gently sloping base, indistinct border
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Type II · Distinct border, no constriction
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Type III · Constriction without a stalk
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Type IV · Pedunculated
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Notes
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Assessment · Macroscopic type only
Yamada
Type I
Gently sloping base, indistinct border
Base
Gently sloping; the border with surrounding mucosa is indistinct
Stalk
No constriction and no stalk
Type II
Distinct border, no constriction
Base
Distinct border without constriction
Stalk
None
Type III
Constriction without a stalk
Base
Constriction is present
Stalk
No definite stalk (subpedunculated)
Note: Often close to Paris 0-Isp. The correspondence is not exact.
Type IV
Pedunculated
Base
A definite stalk is present
Stalk
Present (pedunculated)
Note: Close to Paris 0-Ip.
Notes
Assessment
Macroscopic type only
Scope
Macroscopic classification by the base only. Histology and depth are not included
Paris
0-IIa often maps to I/II, 0-Is to II/III, and 0-Ip to IV, but the systems are not interchangeable
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Decision support only. Follow current guidelines and local protocols. Classification definitions and terminology follow the original publication language.