Beneficial use of magnifying endoscopy with narrow-band imaging for diagnosing a patient with squamous cell carcinoma of the anal canal.

The patient was a 74-year-old woman. She visited a dermatology clinic with a complaint of discomfort in the anal region. Erosion was observed in the anal region, and biopsies were performed. She was diagnosed with Bowen's disease and was referred to the dermatology department of our hospital for treatment. At our department, an endoscopic examination was performed for assessing the extent of Bowen's disease in the rectum. A retroflexed view of the anal canal revealed a slightly raised lesion with a faded color and an irregular surface. Narrow-band imaging (NBI) revealed a whitish lesion with a relatively clear margin and brown dots on the inside. Magnifying endoscopy with NBI revealed abnormal microvessels with dilatation, tortuosity, caliber change and various shapes, which were quite similar to the intrapapillary capillary loop patterns of superficial esophageal cancer. A complete transanal resection of the anal mucosa was performed thereafter. The patient was diagnosed with a well-differentiated squamous cell carcinoma on the basis of a pathological examination. An early diagnosis is critical for successful treatment of anal canal cancer. In this regard, magnifying endoscopy with NBI may be useful for determining the presence and extent of anal canal cancer.