Definitions

Terms used across the tools, grouped and searchable.

Histology

Adenoma (conventional): Tubular, tubulovillous or villous adenoma. 'Advanced adenoma' = ≥10 mm, villous component, or high-grade dysplasia.
Sessile serrated lesion (SSL / SSP / SSA): Serrated polyp with distorted crypt architecture; precursor of ~15–30% of CRC via the serrated pathway. Counted separately from adenomas in the USMSTF tables.
Traditional serrated adenoma (TSA): Uncommon serrated lesion with eosinophilic cytoplasm and ectopic crypts, usually left-sided; followed at 3 years.
Hyperplastic polyp (HP): Serrated polyp without dysplasia or crypt distortion. Small distal HPs carry no increased risk; HPs ≥10 mm or >20 HPs warrant closer follow-up.
High-grade dysplasia (HGD): Includes older terms 'carcinoma in situ' and 'intramucosal carcinoma'. Does not by itself warrant surgery if the polyp is completely resected.

Endoscopy

Piecemeal resection: Removal of a lesion in more than one piece. For adenomas/SSLs ≥20 mm this mandates a 6-month site check for residual neoplasia.
High-quality colonoscopy: Cecal intubation, adequate preparation (able to detect polyps >5 mm), adequate withdrawal (≥6 min), and complete polyp resection. USMSTF intervals assume this.
Adequate bowel preparation: Preparation sufficient to detect polyps >5 mm (e.g., Boston Bowel Prep Score ≥2 in each segment). If inadequate, repeat within 1 year.

Hereditary

Cumulative adenoma count: Lifetime total across all colonoscopies — the number that drives germline testing thresholds (≥20 recommended, 10–19 suggested).
Multigene panel testing (MGPT): Germline NGS panel. ACG 2026 minimum gene set: APC, AXIN2, BMPR1A, EPCAM, GREM1, MLH1, MSH2, MSH3, MSH6, MUTYH, NTHL1, POLD1, POLE, PMS2, PTEN, SMAD4, STK11.
FAP / attenuated FAP: Autosomal dominant APC syndromes. Classic FAP: >100 adenomas, onset in teens; AFAP: 10–100 adenomas, later onset, right-sided predominance.
MUTYH-associated polyposis (MAP): Autosomal recessive (biallelic MUTYH). Typically 10–100 adenomas, onset 40s–50s; monoallelic carriers have modestly elevated CRC risk.
Polymerase proofreading-associated polyposis (PPAP): Autosomal dominant POLE/POLD1 exonuclease-domain variants; oligo-polyposis with early CRC, endometrial and other tumors.
Colonic polyposis of uncertain etiology (CPUE): Polyposis phenotype with a negative germline panel. Consider APC mosaicism testing; manage by cumulative colorectal and duodenal adenoma burden.
Spigelman stage: Duodenal polyposis score from polyp number, size, histology and dysplasia (1–3 points each). Stage 0 = 0, I = 1–4, II = 5–6, III = 7–8, IV = 9–12.
CHRPE: Congenital hypertrophy of the retinal pigment epithelium. Bilateral or multifocal lesions are an extracolonic FAP feature that triggers testing.
Cribriform-morular thyroid carcinoma (CMTC): Rare thyroid cancer strongly associated with APC variants; formerly 'cribriform-morular variant of papillary thyroid carcinoma'.
Desmoid tumor: Locally aggressive fibromatosis; occurs in ~10–30% of FAP, often intra-abdominal after surgery. A personal history triggers germline testing.
Serrated polyposis syndrome (SPS): WHO 2019: ≥5 serrated lesions proximal to the rectum all ≥5 mm with ≥2 ≥10 mm, OR >20 serrated lesions of any size throughout the colon (≥5 proximal). Surveillance usually every 1–3 years.

Evidence

Strength of recommendation (GRADE): Strong = most patients should receive it. Weak / conditional = the right choice varies by patient values and circumstances.
Quality of evidence (GRADE): High: further research unlikely to change the estimate. Moderate: may change it. Low / very low: likely to change; estimate uncertain.