Anterolateral Thigh Island Flap Reconstruction After Margin-Positive, Sphincter-Preserving Excision of Scrotal Extramammary Paget’s Disease: A Case Report

Background/Objectives: Extramammary Paget’s disease (EMPD) of the scrotum, a rare intraepithelial adenocarcinoma, closely mimics benign dermatoses and is often diagnosed only after years of unsuccessful topical treatment. Because tumor cells extend beyond the visible border, wide excision often leaves large defects and positive margins. When disease reaches the perianal skin, clearance may cost anorectal function. Case: A 69-year-old male had been treated for presumed scrotal eczema for 9 years before punch biopsy established EMPD extending from the scrotum across the perineum to the medial thigh and anal verge. After wide excision with a 2-cm margin, frozen section showed intraepidermal Paget cells at the perianal margin; because clearance risked sphincter resection, further excision was withheld. The continuous defect was reconstructed with an 18 × 12 cm anterolateral thigh (ALT) island flap. The flap survived completely. Medical oncology recommended surveillance, with radiotherapy or systemic therapy reserved for progression. The site remained stable at 6 months; the patient was then lost to follow-up untreated. Conclusions: When a positive margin is accepted to preserve function, tissue that can be re-elevated, tolerates irradiation, and leaves residual disease accessible to inspection is a reasonable choice, although this remains untested here and the oncologic outcome is unknown.