Villous Adenoma: Symptoms and Management
Clinical Presentation
Villous adenomas most commonly present with rectal bleeding, mucus discharge, diarrhea, and urgency, with distal lesions often causing a palpable mass on digital rectal examination.
Common Symptoms
- Rectal bleeding is the most frequent presenting symptom 1, 2, 3
- Mucus discharge occurs commonly, particularly with large villous adenomas due to their secretory nature 1, 2
- Diarrhea is a characteristic symptom related to the villous architecture and mucus production 3
- Urgency and change in bowel habits may occur, especially with larger lesions 2
- Palpable mass on digital rectal examination, described as soft, velvety, and flat with mucus discharge 1
Less Common Presentations
- Iron deficiency anemia from chronic occult bleeding 4
- Abdominal pain in atypical cases 5
- Melena with more proximal lesions 5
- Obstruction with very large lesions 2
- Bowel perforation (extremely rare complication) 5
Critical Risk Assessment
The malignant potential of villous adenomas is substantial and directly correlates with size, making complete resection mandatory.
Malignancy Risk Stratification
- Villous adenomas >1 cm with villous histology are classified as "advanced adenomas" with significant malignant potential 4, 6
- 50% of adenomatous polyps >2 cm contain foci of adenocarcinoma 4
- Giant villous adenomas (>8 cm) carry an 83% combined risk of dysplasia/malignancy, with 50% showing dysplasia and 33% frank malignancy 1
- Villous adenomas >2 cm have up to 50% risk of malignancy 1
- 42% of polyps considered benign on preoperative biopsy showed malignant transformation when the entire specimen was examined 2
High-Risk Features Requiring Surgical Resection
- Grade 3 or 4 histology 6
- Angiolymphatic invasion 6
- Positive margin of resection 6
- Tumor budding 7
- Poor tumor differentiation 7
Management Algorithm
Endoscopic Management (First-Line)
All villous adenomas should be completely removed endoscopically with en bloc resection when technically feasible.
- Complete en bloc resection is mandatory for proper histological examination 6, 7, 8
- Hot snare polypectomy is recommended for pedunculated lesions ≥10 mm 6, 8
- Prophylactic mechanical ligation (detachable loop or clips) is recommended for pedunculated lesions with head ≥20 mm or stalk thickness ≥5 mm to reduce bleeding risk 6
- Mark the polyp site at colonoscopy if cancer is suspected or within 2 weeks when pathology confirms concerning features 6
- Document size, number, location, and completeness of removal for future surveillance planning 6, 8
Surgical Management (When Endoscopic Resection Inadequate)
Surgical resection is required for lesions too large for safe endoscopic removal or when unfavorable histopathologic features are present.
- Laparoscopic or open segmental colectomy is indicated for giant villous adenomas not amenable to endoscopic or transanal resection 1, 2
- Colectomy with en bloc lymph node removal is mandatory for lesions with unfavorable histology 6
- Transanal resection may be considered for smaller distal rectal lesions, though recurrence rates are higher (26.7% vs 6.7% for segmental colectomy) 2, 9
- Laparoscopic ultra-low anterior resection with colo-anal anastomosis is safe and effective for circumferential giant rectal villous adenomas 1
Management of Malignant Polyps
- No additional surgery needed for completely resected pedunculated or sessile polyps with grade 1 or 2 histology, no angiolymphatic invasion, and negative resection margin 6, 8
- Colectomy remains an option for sessile polyps even with favorable features due to 10% risk of lymph node metastases 6
Surveillance Strategy
Patients with villous adenomas require colonoscopy in 3 years due to high-risk classification.
- 3-year surveillance interval is mandatory for villous adenomas regardless of size 6, 8
- Multiple adenomas (≥3) or large size (≥1 cm) further increases risk, with 49% developing advanced adenoma at first follow-up 6
- Normal surveillance colonoscopy reduces subsequent adenoma detection rate from 40% to 10% 6
- Yearly surveillance may be appropriate for patients with multiple polyps, large size, or highest grade of dysplasia 4
Critical Pitfalls to Avoid
- Never rely on preoperative biopsy alone to exclude malignancy—42% of "benign" biopsies showed malignancy on full pathologic examination 2
- Incomplete polyp removal is a critical error leading to higher recurrence rates, particularly with local resection techniques 8, 2
- Ensure high-quality baseline colonoscopy with adequate bowel preparation, complete cecal examination, and minimum 6-minute withdrawal time for accurate risk assessment 6, 8
- Proper pathologic sectioning is essential—bisect the polyp through the center of the stalk to visualize the mucosa/submucosa junction and assess margins 7, 8
- Synchronous neoplasia occurs in 30% of patients with adenomatous polyps, requiring careful evaluation of the entire colon 4