Revised Bethesda Guidelines

Criterion 1

CRC diagnosed in patient < 50 years of age

Criterion 2

Synchronous or metachronous CRC, or other Lynch-associated tumour (endometrial, stomach, ovary, pancreas, ureter, renal pelvis, biliary tract, brain, small bowel, sebaceous glands) — any age

Criterion 3

CRC with MSI-high histology (TIL, Crohn's-like reaction, mucinous/signet ring differentiation, medullary pattern) — diagnosed < 60 years

Criterion 4

CRC in ≥ 1 first-degree relative with Lynch-associated tumour, with ≥ 1 cancer diagnosed < 50 years

Criterion 5

CRC in ≥ 2 first- or second-degree relatives with Lynch-associated tumours — any age