Impact of endoscopic submucosal dissection of an anal squamous intraepithelial lesion with indistinct border
17 September 2019 (online)
A 35-year-old woman, with negative results from a human immunodeficiency virus (HIV) antibody test, underwent colonoscopy that revealed whitish nodules and elevated papillary lesions of various sizes situated in the anal transitional zone ([Fig. 1]). Biopsy of the whitish nodules revealed high grade squamous intraepithelial lesions. The protruding lesions were distributed almost circumferentially. It was difficult to identify the lateral margins of the high grade squamous intraepithelial lesions with magnified narrow band imaging (NBI) ([Fig. 1 c], [Fig. 2 a, b]) and indigo carmine dye spraying ([Fig. 1 b]).
We performed diagnostic circumferential resection of the involved area via endoscopic submucosal dissection (ESD) ([Video 1]).
Video 1 Endoscopic submucosal dissection (ESD) of an anal squamous intraepithelial lesion with an indistinct border.
The procedure was done using a gastroscope (Olympus, Japan) capped with a small-caliber tip attachment (ST Hood short type; Fujifilm, Japan). For local anesthesia a 1:1 mixture of 1 % lidocaine and Glyceol (10 % glycerol and 5 % fructose in normal saline solution; Chugai Pharmaceutical, Japan) was injected into the anal aspect of the lesion. ESD was performed using a bipolar needle-knife with a waterjet function (Jet B-knife; Xemex, Japan) and an insulated-tip electrosurgical knife (IT-knife nano; Olympus). The lesion was resected en bloc, uneventfully.
The pathological findings were of low grade squamous intraepithelial lesion in the protruding lesions and high grade squamous intraepithelial lesion in the flat area ([Fig. 3], [Fig. 4]). The vertical margin was free of tumor, but the anal horizontal margin was difficult to evaluate because of epithelial exfoliation. There was no lymphovascular invasion. Follow-up colonoscopy in 1 year is scheduled.
High grade squamous intraepithelial lesions are precancerous lesions which may progress to invasive cancer , and their management has not been established . We have previously reported the efficacy of performing ESD on early anal canal cancer . Chromoendoscopy and NBI with magnification are useful in delineating the margins of early anal canal cancer  . However, it was difficult to delineate the margin even using both methods in this case. The recognition of high grade squamous intraepithelial lesions with indistinct borders, as in this case, is paramount in the prevention of advanced cancer.
Endoscopy E-Videos is a free access online section, reporting on interesting cases and new techniques in gastroenterological endoscopy. All papers include a high
quality video and all contributions are
freely accessible online.
This section has its own submission
- 1 Watson AJM, Smith BB, Whitehead MR. et al. Malignant progression of anal intra-epithelial neoplasia. ANZ J Surg 2006; 76: 715-717
- 2 Alam NN, White DA, Narang SK. et al. Systematic review of guidelines for the assessment and management of high-grade anal intraepithelial neoplasia (AIN II/III). Colorectal Dis 2016; 18: 135-146
- 3 Chou Y, Saito Y, Matsuda T. et al. Novel diagnostic methods for early-stage squamous cell carcinoma of the anal canal successfully resected by endoscopic submucosal dissection. Endoscopy 2009; 41: E283-E285
- 4 Yamaguchi T, Moriya Y, Fujii T. et al. Anal canal squamous-cell carcinoma in situ, clearly demonstrated by indigo carmine dye spraying: report of a case. Dis Colon Rectum 2000; 43: 1161-1163
- 5 Oono Y, Fu K, Nakamura H. et al. Narrowband imaging colonoscopy with a transparent hood for diagnosis of a squamous cell carcinoma in situ in the anal canal. Endoscopy 2010; 42: E183-E184