P1964 - A Rare Case of Secondary Perianal Paget's Disease

Colin Westman, DO, MS¹, Vignesh Krishnan Nagesh, MBBS², Shawn Philip, DO³, Davood K Hosseini, MD³, Nazir Ahmed, MD³, Kunchang Song, MD⁴, John Sotiriadis, MD, PhD, FACG^2
1Hackensack Meridian Health - Palisades Medical Center, Hackensack, NJ; ²Hackensack Meridian Palisades Medical Center, North Bergen, NJ; ³Hackensack University Medical Center, Hackensack, NJ; ⁴Hackensack Meridian Health - Palisades Medical Center, North Bergen, NJ

Introduction: Perianal Paget’s Disease (PPD) is a form of Extramammary Paget’s Disease consisting of intraepithelial invasion of the perianal skin. It can present as a primary neoplasm of the perianal skin or as secondary spread from an underlying anorectal invasive carcinoma. The condition is exceedingly rare, representing less than 1% of anal disease and 1.3% of all Paget’s Disease. Herein, we provide a case report of a patient with secondary PPD.

Case Description/Methods: A 50 year old male presented three years ago complaining of perianal pruritus, pain, and blood when wiping. Physical examination of the patient revealed a well-circumscribed, erythematous perianal lesion. Subsequent elective incisional biopsy of the lesion revealed a polypoid lesion with tumor cells containing intracytoplasmic mucin (Figure 1B and 1C). These stained positive for CK7, CK20, CDX2 and negative for GCDFP-15, consistent with secondary PPD. Further workup with and computed tomography was unrevealing for synchronous lesions. The patient was then lost to follow-up until he presented to the gastroenterology office this year with reports of anal pruritus and bleeding. On examination, there was an excoriated, erythematous plaque spreading 4 cm circumferentially around the anal canal (Figure 1A). Repeat exam under anesthesia for biopsy and a colonoscopy are scheduled.

Discussion: PPD is a rare condition, most often diagnosed in the 6^th and 7^th decades of life and usually presents as a primary intraepithelial malignancy. Secondary PPD, which is associated with an underlying anorectal malignancy, is much rarer. In a prior review of the National Cancer Center Hospital database, 14 cases of secondary PPD were identified between 2006 – 2021. It is typically described as an erythematous, eczematous lesion involving the perianal skin. Histology shows characteristic Paget cells, which are large cells with abundant, pale cytoplasm and large nuclei. In primary PPD, cells are positive for CK7 and GCDFP-15. In secondary PPD cells are positive for CK7, CK20, and CDX2, but negative for GCDFP-15. The management of PPD is poorly defined due to the lack of data. It usually includes excision of the underlying skin lesion as well as evaluation for the spread of malignancy, both endoscopically and radiographically. This case raises awareness for inclusion of PPD in the differential diagnosis under the appropriate circumstances.



Disclosures:


Colin Westman, DO, MS¹, Vignesh Krishnan Nagesh, MBBS², Shawn Philip, DO³, Davood K Hosseini, MD³, Nazir Ahmed, MD³, Kunchang Song, MD⁴, John Sotiriadis, MD, PhD, FACG². P1964 - A Rare Case of Secondary Perianal Paget's Disease, ACG 2024 Annual Scientific Meeting Abstracts. Philadelphia, PA: American College of Gastroenterology.