Rationale:Extramammary Peget disease (EMPD) is a rare tumor, which typically occurs in the perianal regions. Perianal Paget disease (PPD) was first reported in 1893, and which has only 180 cases that have been reported in literature. The rarity of the disease means that no large studies have been made, and so the optimal treatment for this disease still remains controversial.Patient concerns:In this case, we reported a 65-years-old female patient with PPD. The patient suffered intermittent pruritus in the perianal region for 1 year. She had neither genitourinary nor gastrointestinal symptoms. Local examination revealed a whitish gray skin lesion in the left perianal area with a 3 × 3 cm size.Diagnoses:The perianal skin biopsy was consistent with EMPD. Then the patient underwent a screening colonoscopy, gynecological ultrasonography, and whole-body computed tomography to exclude underlying malignancy.Interventions:The patient underwent wide local excision with margin control by frozen section examination and posterior thigh flap reconstruction. Subsequently follow-up remains 6 years.Outcomes:The operation was successful. The total operation time was 296 minutes, and the estimated blood loss was 120 mL. The patient recovered without any complication and discharged home on the sixth postoperative day. After 6 years’ follow-up, there was no evidence of recurrence and no influence in the anal bowel control function.Lessons:PPD is a rare disorder; the current knowledge on diagnose and treatment is based on small case series. Thus, it is complicated to elaborate a consensus on diagnostic and treatment guidelines. Wide local excision remains the treatment of choice with a variety of adjuvant therapies. Our method has an advantage which is the posterior thigh flap could be designed in accordance with the defect of the perianal. It is mandatory that the patient must accept a long-term follow-up to detect local recurrence and to distant carcinoma.