We report a case of a 53-year-old woman who underwent ALTA therapy and anal mucosal resection for internalhemorrhoids and mucosal prolapse at another hospital 1 year and 4 months ago. However, her anal pain and swelling did not improve. She had a preoperative diagnosis of postoperative external hemorrhoids and sentinel pilesassociated with anal fissure. The patient underwent hemorrhoidectomy and anoplasty at our hospital. Postoperativepathological diagnosis revealed perianal Bowen’s disease. Bowen’s disease is an intraepidermal squamous-cellcarcinoma (carcinoma in situ), and its occurrence around the anus is extremely rare. There have been no reports ofperianal Bowen’s disease in patients who have received ALTA therapy. Two years have passed since the operation,and no recurrence has been observed. We report our experience with perianal Bowen’s disease diagnosed duringintractable pain treatment after receiving ALTA therapy