Narrow-band imaging for diagnosis of squamous cell carcinoma in the anal canal

Yoji Takeuchiab, Artur Nemethb, Otto Ljungbergc, Ervin Tothb, Henrik Thorlaciusd

Osaka Medical Center for Cancer and Cardiovascular Diseases, Osaka, Japan; Malmö, Skåne University Hospital, Lund University, Malmö, Sweden

aDepartment of Gastrointestinal Oncology, Osaka Medical Center for Cancer and Cardiovascular Diseases, Osaka, Japan (Yoji Takeuch); bDepartment of Clinical Sciences, Section of Endoscopy (Yoji Takeuchi, Artur Nemeth, Ervin Toth); cDepartment of Clinical Sciences, Section of Pathology (Otto Ljungberg); dDepartment of Clinical Sciences, Section of Surgery (Henrik Thorlacius), Malmö, Skåne University Hospital, Lund University, Malmö, Sweden

Correspondence to: Henrik Thorlacius, M.D, Ph.D., Department of Clinical Sciences, Malmö, Section of Surgery, Skåne University Hospital, Lund University, 205 02 Malmö, Sweden, Tel.: +46 40 331000, Fax: +46 40 336207, e-mail: henrik.thorlacius@med.lu.se
Received 27 November 2016; accepted 6 December 2016; published online 22 December 2016
DOI: https://doi.org/10.20524/aog.2016.0115
© 2017 Hellenic Society of Gastroenterology

A 61-year-old man with a history of rectal bleeding and hemorrhoids underwent colonoscopy and a 15 mm large flat lesion with scattered reddish spots was detected in the anal canal at the dentate line (Fig. 1A). Narrow-band imaging showed dilated, tortuous, and irregular microvessels with intraepithelial papillary capillary loop patterns (Fig. 1B), similar to squamous cell carcinoma of the esophagus [1,2]. The lesion was treated by underwater endoscopic mucosal resection without submucosal injection. The polyp was completely immersed in water, the lumen was deflated (Fig. 1C), and a polypectomy snare (13 mm, Captivator™, Boston Scientific) was used to resect it in two pieces with a piecemeal technique. The lesion was completely removed without any bleeding or signs of perforation (Fig. 1D). The patient went home the same day and experienced no complication. Pathology showed a poorly differentiated squamous cell carcinoma (Fig. 2) with positive staining for P16, a marker of human papilloma virus infection, and Ki-67, but the level of invasion was uncertain and the patient was referred for chemoradiotherapy.

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Figure 1 (A) Endoscopic view of a 15-mm large lesion in the anal canal at the dentate line. (B) Narrow-band imaging reveals a microvascular pattern of dilated, tortuous, and irregular capillaries with intraepithelial papillary vascular loops. (C) The lesion was treated by underwater endoscopic mucosal resection. (D) The polyp was completely removed by piecemeal resection

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Figure 2 Microscopic image showing poorly differentiated squamous cell carcinoma

Squamous cell carcinoma of the anal canal is a rare cancer in the gastrointestinal system [3] and can easily be overlooked during colonoscopy. This unusual case shows that digital chromoendoscopy using narrow-band imaging can be useful to help identify anal squamous cell carcinoma.

References

1. Yoshida T, Inoue H, Usui S, Satodate H, Fukami N, Kudo SE, Narrow-band imaging system with magnifying endoscopy for superficial esophageal lesionsGastrointest Endosc 2004; 59: 288-295.

2. Inoue H, Kaga M, Ikeda H, Magnification endoscopy in esophageal squamous cell carcinoma: a review of the intrapapillary capillary loop classificationAnn Gastroenterol 2015; 28: 41-48.

3. Clark MA, Hartley A, Geh JI, Cancer of the anal canalLancet Oncol 2004; 5: 149-157.

Notes

Conflict of interest: None