# Gallbladder Polyps: Pathology and Reporting

> Gallbladder polyps for NEET-PG Pathology: cholesterol polyps, adenomas, dysplasia-carcinoma sequence, incidental carcinoma staging and T1b surgery.

- Canonical URL: https://prepelephant.com/topics/neet-pg/pathology/gallbladder-polyps-pathology
- Exam / course: NEET-PG · Subject: Pathology
- Publisher: PrepElephant (https://prepelephant.com) — Prepared and reviewed by the PrepElephant Academic Review Team
- First published: 2026-10-02
- Last updated: 2026-10-02
- How to cite: "Gallbladder Polyps: Pathology and Reporting", PrepElephant, https://prepelephant.com/topics/neet-pg/pathology/gallbladder-polyps-pathology

## Direct answer

Gallbladder polyps divide into pseudopolyps and true neoplasms. Cholesterol polyps — foam-cell (xanthomatous) nodules on a fragile stalk — account for roughly 60% and are benign; adenomas are uncommon, and the dominant route to gallbladder carcinoma is not the adenoma-carcinoma sequence but a flat dysplasia-to-carcinoma progression in a chronically inflamed, stone-bearing gallbladder. Risk factors that convert a polyp into a surgical problem are size ≥10 mm, age over 50-60 years, sessile morphology, solitary lesions, primary sclerosing cholangitis and coexisting gallstones; cholecystectomy is advised at ≥10 mm, or at smaller sizes with those risk factors. Gallbladder carcinoma itself is a disease with striking Indian relevance — rates in northern Indian women are among the highest recorded anywhere, firmly linking it to the subcontinental gallstone belt.

## What you must remember

- **Cholesterol polyp histology:** branching papillary fronds of foamy macrophages beneath normal epithelium, often multiple and small, part of the cholesterolosis spectrum with the "strawberry gallbladder" gross appearance.
- **Adenoma types:** tubular, tubulovillous, villous — pedunculated, dysplastic epithelium over non-neoplastic stroma, genuinely rare in the gallbladder compared with the colon.
- **The dominant precursor:** flat dysplasia spreading through the mucosa before invasion — biliary papillary intraepithelial neoplasia (BilIN) is the terminology used for the flat and papillary precursors.
- **Management thresholds:** cholecystectomy for polyps ≥10 mm, or ≥6 mm with risk factors (age over 60, PSC, sessile or rapidly growing lesion, Indian ethnic origin is cited in some guidelines as a risk modifier); surveillance ultrasound otherwise.
- **Incidental carcinoma protocol:** every cholecystectomy specimen is opened entirely and sampled — one block per centimetre of any thickened or suspicious wall is a commonly quoted discipline, because T1a tumours are found only by looking.
- **T-stage decisions:** T1a (lamina propria only) is cured by cholecystectomy; T1b (into the muscular layer) demands extended cholecystectomy with portal lymphadenectomy — the single most examinable sentence in gallbladder pathology.
- **Porcelain gallbladder:** calcified wall from chronic inflammation, historically an indication for cholecystectomy for carcinoma risk.
- **Xanthogranulomatous cholecystitis:** foamy macrophage sheets and fibrosis obliterating the wall — a notorious radiological and frozen-section mimic of carcinoma, and common in Indian practice.

## From ultrasound to the surprise on the cut-up bench

A 52-year-old woman undergoes laparoscopic cholecystectomy for a 9 mm polyp with stones. Frozen section is not requested. Permanent sections show a cholesterol polyp — but a separate 6 mm firm area near the fundus reveals a moderately differentiated adenocarcinoma infiltrating through the muscular layer into the perimuscular connective tissue: T1b at minimum. The report must now answer three questions with total clarity: the deepest point of invasion relative to the muscular layer (T1b versus T2, T2 subdividing into T2a peritoneal-sided and T2b hepatic-sided in the AJCC 8th edition, hepatic-sided being worse), the cystic duct margin status, and whether the serosal ink is involved. Because the depth crossed into muscle, she is referred for extended cholecystectomy with en-bloc liver bed resection and portal nodal dissection — the operation that improves survival for T1b and beyond, plus consideration of adjuvant capecitabine-based chemotherapy for node-positive disease.

The preventive logic sits upstream: in the Indian gallstone belt, where gallbladder carcinoma is among the leading gastrointestinal cancers in women, symptomatic gallstones get surgery rather than watchful waiting, and every specimen gets the full open-and-sample protocol regardless of the preoperative label.

## Where students slip

Candidates over-invest in the polyp and under-invest in the wall. Exam questions about a "polyp" actually test the incidental-carcinoma pathway, and the answer that scores is the T1a/T1b fork — cholecystectomy alone versus extended cholecystectomy. The second slip is histological: Rokitansky-Aschoff sinuses (mucosal herniations into or through muscle) lined by dysplastic epithelium can look deceptively like invasive carcinoma; invasion is judged by desmoplastic stromal reaction and disorganised glands beyond the R-A sinus framework. Third, xanthogranulomatous cholecystitis: at frozen section, the macrophage-rich wall can be misread as poorly differentiated carcinoma, an error with real operative consequences — the safe answer reports "inflammation, defer for permanent sections" when certainty is absent.

## Frequently asked questions

### Which gallbladder polyp is most common?

The cholesterol polyp — a papillary accumulation of lipid-laden macrophages, usually multiple and under 10 mm, with no malignant potential.

### At what polyp size is cholecystectomy recommended?

Ten millimetres or more, or 6 mm and above in the presence of risk factors such as age over 60, primary sclerosing cholangitis, sessile morphology or rapid growth.

### Why does T1b carcinoma require more than cholecystectomy?

Muscular-layer invasion carries substantial nodal metastasis risk, so extended cholecystectomy with portal lymphadenectomy — and liver-bed resection — becomes the standard.

### What is xanthogranulomatous cholecystitis?

A chronic inflammatory process with sheets of foamy macrophages and fibrosis that thickens and fixes the gallbladder, classically mimicking carcinoma clinically and on frozen section.

### How are T2 gallbladder carcinomas substaged in the AJCC 8th edition?

By side of involvement — T2a peritoneal-sided versus T2b hepatic-sided, with hepatic-sided tumours carrying worse survival and more aggressive surgery.