Nonpalpable lesions of the colon can be difficult to locate intraopera
tively. We have demonstrated in an experimental study in dogs that the
colon can be endoscopically 'tattooed' by injecting dye through a fle
xible needle into the wall of the colon. At laparotomy, the resulting
''tattoo'' is then visible on the serosal surface of the bowel. This t
echnique allows precise surgical localization of endoscopically identi
fied lesions simply by visualizing the dye. Our initial clinical exper
ience tattooing 15 colonic lesions in 12 patients is presented. In all
patients, the endoscopically injected dye (1 per cent indocyanine gre
en) was easily visualized on the serosal surface of the colon at surge
ry. The dye remained at the site of injection for at least 36 hours al
lowing tattooing to be performed the day before surgery. No significan
t complications were encountered with only one patient developing an i
nflammatory reaction at the site of injection. This experience demonst
rates the clinical utility of endoscopic tattooing of the colon to per
mit accurate intraoperative localization of small or nonpalpable lesio
ns.