2022 Volume 64 Issue 6 Pages 1241-1248
A 64-year-old woman underwent a colonoscopy for colon polyp follow-up. Colonoscopy showed three flat elevated lesions 12mm, 7mm and 4mm in diameter at the anal canal. These three lesions had Type B1 vessels based on Magnifying Endoscopy (ME) Classification of the Japan Esophageal Society. A marked increase in nuclear abnormality was observed in these lesions, and they were regarded as equivalent to Type 3 in the endocytoscopy system (ECS)-type classification. Although the biopsy results showed high grade intraepithelial lesions, we diagnosed them as intramucosal canal squamous cell carcinoma. Therefore, all lesions were resected by endoscopic submucosal dissection (ESD). Pathological diagnosis of all the lesions was intramucosal canal squamous cell carcinoma. The 12-mm lesion displayed multiple signs of ductal progression in the submucosal layer and had unclear vertical margins, while the 4-mm lesion had an unclear horizontal margin.
In this case, ME-NBI and ECS seemed to be useful for the diagnosis of intramucosal squamous cell carcinoma at the anal canal, but diagnosis of the precise area of horizontal progression was difficult.
