ABSTRACT Introduction Extramammary Paget's Disease (EMPD) is a rare neoplasm typically found in the genital and perianal region. It typically presents as a pruritic, painful rash and is often mistaken for a fungal infection before biopsy is taken. Staging and biopsy technique have not yet been standardized given the cancer's rarity, leading to a recurrence rate ranging from 21-61% recurrence upon literature review. Objective To analyze outcomes of EMPD patients receiving mapping biopsy prior to tumor excision Methods Retrospective chart review was conducted of 19 EMPD patients treated with biopsy and/or surgery by co-author at our institution from 2013 to 2021. We extracted patient demographic data, length of follow-up time, percent positive biopsy sites, margin status, recurrence status, and other pertinent disease characteristics. Results Within our 19 total patients, median age at diagnosis was 72 with a range between 62 and 88. The majority of patients had a prior history of cancer (13/19), with the most common type being skin cancer (12) followed by prostate cancer (4). No patients were diagnosed with secondary malignancy during mandatory EMPD workup of cystoscopy and colonoscopy before WLE. The majority of patients had not been treated for EMPD prior to presenting to Moffitt (16/19). Of the 16 patients receiving novel mapping biopsy, 8/16 had at least one positive core biopsy site, with a mean of 7% positivity of the total core sites (4/60). Mapping biopsy positive sites helped shape perimeters for wide local excision (WLE) of tumor for patients opting for surgical treatment. Margins of WLE were positive for 11/17 patients. Calculating the length of follow-up time after WLE revealed a median of 6 months, with a range from 0 to 74 months and a mean of 14. No patients received postoperative radiation. One patient did receive topical 5-FU, but use was discontinued after several days due to irritation. Only 1 episode of recurrence was reported during this period of follow-up. Conclusions Our novel mapping biopsy technique is an effective way to delineate surgical margins before WLE. Margin positivity is not an accurate indicator of the likelihood of recurrence for EMPD patients, as only 1/17 saw recurrence post-WLE despite 11/17 with positive margins. Disclosure No