Abstract
Anal canal squamous cell carcinoma (SCC) is rarely diagnosed at an early stage. However, using recent developments in endoscopic equipment, we expect to diagnose early stage anal canal SCC. We report two cases of early anal canal SCC (tumor in situ, Tis) diagnosed using magnifying endoscopy with narrow band imaging (NBI), where transanal local resection was also performed.
[Case 1] The first patient was a 73-year-old woman undergoing screening colonoscopy prior to surgery for gastric cancer. A white, flat, elevated lesion 10 mm in size was identified at the dentate line of the anal canal. Magnifying endoscopy with NBI showed irregular vessels at the anal portion of the elevated lesion. A biopsy specimen from the area revealed SCC. Clinical diagnosis was TisN0M0, and transanal local resection was performed for the purposes of total biopsy. The histopathological diagnosis was squamous cell carcinoma, depth M (Tis), ly0, v0, ow(-), aw(-).
[Case 2] The second patient was a 53-year-old woman undergoing screening colonoscopy prior to surgical treatment of a gallstone. A white, flat, elevated lesion 20 mm in size was identified at the dentate line of anal canal. Magnifying endoscopy with NBI showed irregular vessels. Clinical diagnosis was TisN0M0, and transanal local resection was performed for the purposes of total biopsy. The histopathological diagnosis was squamous cell carcinoma, depth M (Tis), ly0, v0, ow(-), aw(-), TisN0M0, Stage 0. During follow up endoscopy we diagnosed dysplasia in the remaining lesion, with recurrence of SCC identified using magnifying endoscopy with NBI. Surgery was repeated, with local resection of the lesion performed a total of three times. Thereafter, pathological assessment demonstrated HPV-positive, and we diagnosed anal canal SCC due to HPV infection.
In these two cases, magnifying endoscopy with NBI was useful for detection and identification of the demarcation line in early anal canal SCC, especially tumor in situ (Tis).
