Lugol is a vital dye that reacts with the glycogen of malpighian
nonkeratinized epithelia. Normal mucosa is stained brown by Lugol, whereas
pathologic mucosa remains unstained [1]. In smokers and
those with alcohol addiction, Lugol increases the sensitivity of the endoscopic
detection of dysplasia and squamous cell carcinoma of the esophagus
[2]. We wondered whether Lugol might also improve
detection of such lesions in the anal canal of high-risk patients. Indeed, most
of the anal canal is covered with malpighian nonkeratinized epithelium,
separated from the glandular rectal mucosa by a transitional cell
epithelium.
First, we wanted to prove the feasibility of this procedure for the
anal canal, and to test it in patients with anal carcinoma, before and after
treatment. Thus, after perfect cleansing, we sprayed 2 % Lugol by
retroflexion in the rectum with a gastroscope, in eight female patients without
iodine allergy. The patients had squamous cell carcinoma of the anal canal, and
had either not yet been treated (n = 5 examinations, in
five patients), or had been previously treated by radiochemotherapy and did not
show detected recurrence by clinical examination, conventional endoscopy or
endosonography (n = 9 examinations, in five patients).
Overall, two patients underwent the Lugol staining both before and after
radiochemotherapy. Results were assessed after 2 minutes.
All malpighian areas that were endoscopically normal were intensely
and wholly stained by Lugol, whereas the carcinomas that had not yet been
treated and glandular mucosa remained unstained ([Fig. 1] and [2]). Tolerance of
the procedure was good.
Fig. 1 Direct vision: lack of
brown coloration of a squamous cell carcinoma of the anal canal after Lugol
staining.
Fig. 2 Retroflexion vision:
homogeneous brown coloration of the upper part of the anal canal after Lugol
staining in a patient previously treated for a squamous cell carcinoma of the
anal canal without macroscopic recurrence.
In conclusion, we proved the feasibility of Lugol chromoendoscopy of
the anal canal, a procedure not previously described, to our knowledge. So, we
intend to test it further, with the aim of improving the detection of dysplasia
and early carcinoma in high-risk diseases of the anal canal, namely previously
treated squamous cell carcinoma, condylomas [3] and
chronic anal localizations of Crohn’s disease [4]
[5].
Endoscopy_UCTN_Code_CCL_1AD_2AB
