A case of anal canal carcinoma with pagetoid spread that was curatively resected by multiple endoscopic and surgical treatments.

A 57-year-old woman with no significant medical history was referred after a colonoscopy for abdominal distension, which revealed a tumor in the lower rectum. Pre-operative colonoscopy showed the tumor was 12 mm in size, located from the anorectal junction to beyond the dentate line, and was diagnosed as high-grade intramucosal neoplasia or shallow submucosal invasive cancer. Endoscopic submucosal dissection was performed, and the lesion was resected en bloc. Pathological examination revealed moderately differentiated tubular adenocarcinoma with tubulovillous adenoma. The stratified squamous epithelium adjacent to the anal side of the lesion showed pagetoid spread of atypical cells with positive horizontal margins. We referred her to a surgeon for radical treatment. The mucosa surrounding the endoscopic submucosal dissection scar was normal on narrow-band imaging magnification. We marked its oral side endoscopically as the resected boundary. Transanal local excision was performed. The horizontal margins were positive because atypical cells had spread into the stratified squamous epithelium of the anorectal side of the lesion. The patient was followed on an outpatient basis. Sixty days postoperatively, residual tumor growth was observed. The second local resection was performed after mapping biopsy. All resection margins were negative, there was no lymphovascular invasion. One year after surgery, no recurrence was observed. Regarding endoscopic findings, there are no reports of endoscopic findings of the rectal mucosa, or the squamous epithelium of the anus of pagetoid spread. Here, we report a review of perianal Paget's Disease that resulted in difficulties in borderline diagnosis of pagetoid spread, resulting in multiple therapeutic interventions.