Abstract
Perianal Paget's disease is a rare condition, which is not usually accompanied by cancer. Here, a case of anal canal carcinoma with pagetoid spread and inguinal lymph node metastasis, which exhibited a significant response to preoperative chemoradiotherapy (CRT), is presented. A 58-year-old woman was admitted to The University of Tokyo Hospital with a complaint of discomfort around the anus. Physical examination revealed an erythematous inflamed skin lesion in the perianal region and a tumor of 15 mm in diameter detected on palpation in the left inguinal region, which was diagnosed as metastatic adenocarcinoma by excisional biopsy. Colonoscopy revealed moderately differentiated adenocarcinoma of 15 mm in diameter in the anal canal. Skin biopsy of the perianal region revealed an infiltration of pagetoid cells, which were positive for cytokeratin 7, and negative for cytokeratin 20 and gross cystic disease fluid protein 15. Based on these results, the patient was diagnosed as having anal canal adenocarcinoma with pagetoid spread. The patient received preoperative CRT including the bilateral inguinal region. After CRT, robotic-assisted laparoscopic abdominoperineal resection was performed. The macroscopic findings of the surgical specimen confirmed the formation of a scar as a result of the preoperative CRT. Microscopic examination of the anal tumor revealed no residual carcinoma or lymph node metastasis. In conclusion, this case may suggest the potential applicability of preoperative CRT for the local control of anal canal carcinoma with pagetoid spread.