Gastroscholar

Tattoo is localization, not decoration. ASGE 2024 (Bhatt, PMID 39269377) and the 2021 Delphi (Medina-Prado, PMID 33493699) agree on the method: raise a saline bleb, then put sterile carbon into that bleb, distal (anal) to the lesion, generally 1 mL or less per site. Never inject into or under a lesion you might still lift. Cecum and low rectum already have landmarks.

Original GastroScholar summary card for endoscopic colon tattooing. Not an endoscopic photograph.
Original GastroScholar summary card. Not an endoscopic photograph. This page does not invent a SPOT still.

Experienced teaching points

Clinical Pearls

  1. Saline first. Carbon second. Perpendicular deep ink is how you stain peritoneum and mimic endometriosis on the next CT.
  2. Never into or under a lesion that might still be EMR or ESD. Ink in the submucosa is fibrosis (Delphi, PMID 33493699).
  3. Surgery: two or three distal quadrants so the mark is visible no matter how the colon is rotated. Follow-up of a benign scar: one distal bleb is enough.
  4. Skip cecum (ICV, appendix) and distal rectum (anal verge). Low-rectal ink can also confuse MRI staging.
  5. What you do after you mark it: EMR vs ESD, UEMR, cold snare.

GI Endoscopy · 6 min read

Colon Tattoo: Saline Bleb, Carbon Distal, Never Under a Polyp You Still Plan to Resect

Surgery needs marks the laparoscope can see from any rotation. Endoscopic follow-up needs one distal bleb that does not scar the resection plane.

Clinical Bottom Line

Step Do this
When Lesions that surgery or a later endoscopy must find: suspected cancer, large nonpedunculated polyps after piecemeal EMR, sites without a fixed landmark. Delphi 2021 (PMID 33493699).
Agent Sterile carbon suspension (SPOT / SPOT Ex). ASGE 2024 technology review (PMID 39269377). India ink is the older messy alternative, not the default.
Bleb Tangential needle. 0.5-1 mL saline until a true submucosal blister. Then carbon into that blister, generally not more than 1 mL per site.
Where Distal (anal) to the lesion, a few centimeters away, not in the resection plane. Surgery: 2-4 quadrants at the same level. Benign follow-up: one distal mark.
Skip Cecum and distal/mid rectum. Document distance, side, and number of blebs or the surgeon is hunting a rumor.

Why a saline bleb first?

Deep carbon stains the peritoneum, the mesentery, and the next radiologist's report. The 2010 ASGE tattoo review (Kethu, PMID 20883844) already wanted a submucosal bleb. The 2024 update (PMID 39269377) and the Delphi (PMID 33493699) kept it: 79% consensus for saline first, 97% consensus that you never tattoo into or under a lesion still eligible for endoscopic resection. Ink in the submucosa under a polyp is how EMR and ESD get fibrotic and fail.

If the mucosa does not rise, or the ink vanishes, you are transmural. Stop that site. Do not keep pumping. A laparoscopic surgeon would rather have two clean distal quadrants than a black frozen pelvis.

How many marks?

Cancer headed to laparoscopic or robotic resection: enough distal circumferential marks that the serosal stain is visible no matter which way the colon sits. One 12-o'clock bleb is how a tattoo "disappears" behind fat. Benign piecemeal EMR scar: one distal bleb, photographed, distances written. Do not tattoo the scar itself.

Cecum already has the ileocecal valve and the appendiceal orifice. Distal rectum has the anal verge. Extra ink there is noise, and in the low rectum it can interfere with MRI. This page does not restage how to cut the polyp once you have marked it.

Selected references

  1. ASGE Technology Committee; Bhatt A, et al. Submucosal injection fluid and tattoo agents. Gastrointest Endosc. 2024;100:797-806.
  2. Medina-Prado L, et al. When and How To Use Endoscopic Tattooing in the Colon: An International Delphi Agreement. Clin Gastroenterol Hepatol. 2021;19:1038-1050.
  3. ASGE Technology Committee; Kethu SR, et al. Endoscopic tattooing. Gastrointest Endosc. 2010;72:681-685.

Last reviewed September 20, 2026. Written for clinicians marking a cancer for laparoscopic resection or a piecemeal EMR scar they must find again in six months.

Topics

For your teaching file

Save this article as a PDF

Drop your email and we'll open a print-ready version you can save as a PDF — and you'll start getting our weekly GI endoscopy newsletter.

Save as PDF

Endoscopic Tattooing: 2026 Guidelines and Best Practices

Enter your email — we'll open a clean print-ready version of this article. Choose Save as PDF in the print dialog to download.

Free, no spam. Gastroscholar newsletter. Unsubscribe anytime.

← All articles