When precise anatomical location of a lesion is essential for endoscopic follow-up
after resection, the colonic mucosa is commonly tattooed by submucosal injection of
India ink [1]
[2]
[3]. Our early experience [4] seems to suggest a role of endocytoscopy (ECS) for improving detection of early
recurrences of high risk and/or malignant adenomas. However, potential imaging artifacts
induced by previous tattooing led us to investigate limitations, if any, of ECS under
these circumstances.
Ex vivo ECS was performed in two patients who had undergone surgical resection of
the colon for large adenomas, which had been marked preoperatively using India ink.
A prototype Olympus XEC-300-U endocytoscope (Olympus Medical System Co., Tokyo, Japan)
was used according to the technique described previously [4].
In both cases we observed multiple brownish-yellow, blurred round structures, with
regular borders, corresponding to colonic crypts within tattooed areas ([Fig. 1]). Compared with the normal endocytoscopic appearance of the surrounding mucosa ([Fig. 2]), poor imaging of glandular structures made it nearly impossible to evaluate minimal
changes and/or nuclear atypia, if any, of epithelial cells. The interstitial space
was normally stained with methylene blue. Submucosal black staining was not visualized
by ECS, as expected. The tattooed areas studied by ECS were then examined pathologically.
Microscopic examination with hematoxylin and eosin (H&E) revealed that the mucosa
was normal whereas many black-stained macrophages were distributed throughout the
entire submucosa and partially within the muscularis propria ([Fig. 3]).
Fig. 1 Endocytoscopic picture (× 450) of colonic mucosa after tattooing. Crypts appear as
yellowish structures.
Fig. 2 Normal endocytoscopic image of colonic mucosa surrounding tattooed area.
Fig. 3 Tattooed area that was initially examined using endocytoscopy (ECS), with hematoxylin
and eosin (H&E) staining (× 400). The mucosa is normal, whereas deposits of India
ink pigment are evident in the submucosa.
The ECS findings could be explained by the anatomy of crypts, whose deep branches
through the mucosal layer get closer to the submucosal Indian ink. Black pigment is
likely to interfere optically with the staining of crypts, whereas the interstitial
connective tissue surrounding the glandular necks appears normally stained by methylene
blue.
Poor imaging of glandular details may limit the use of ECS for surveillance examinations
after tattooing. When ECS is scheduled, a modified tattooing technique [5] probably
should be adopted.
Endoscopy_UCTN_Code_CPL_1AJ_2AB
