Nonmass-forming type anorectal cancer with pagetoid spread: A report of two cases.

Pagetoid spread (PS) of anorectal cancer is relatively rare and associated with poor prognosis. While a primary tumorous lesion is usually obvious in most PS cases, we experienced two cases of nonmass-forming type anorectal cancer with PS. It remains challenging to decide strategies. In both cases, histological findings of a perianal skin biopsy showed proliferation of atypical cells that were positive for cytokeratin (CK) 7, CK20, and caudal type homeobox 2 and negative for Gross cystic disease fluid protein 15, suggesting PS. Abdominoperineal resection (APR) with extensive anal skin resection was performed in both patients. The pathological diagnosis in each was nonmass-forming type anorectal cancer with PS. Neither has experienced recurrence in postoperative courses. Even nonmass-forming type anorectal cancer with PS could have high malignant potentials. APR with lymph nodes dissection and wide skin excision and regular surveillance might be necessary.