Pagetoid spread of anal gland adenocarcinoma in situ a clinicopathological case report

Secondary perianal Paget’s disease (PPD) is a rare clinical entity resulting from the intraepithelial dissemination of an underlying adenocarcinoma, yet cases involving anal gland adenocarcinoma in situ with generalized pagetoid spread remain exceptionally rare and poorly documented in existing literature. We present the case of a 62-year-old female with a three-year history of persistent perianal pruritus and exudation whose initial physical examinations and systemic imaging (CT, MRI, and colonoscopy) failed to reveal a visible malignancy. Following wide local excision and comprehensive histopathological sampling of the specimen, a microscopic focus of well-differentiated anal gland adenocarcinoma in situ was identified, manifesting with extensive pagetoid spread into the epidermis. Immunohistochemical analysis confirmed the diagnosis through positivity for CK7, CK20, and CDX-2, alongside negative staining for GCDFP-15 and mammaglobin, while p53 expression showed a wild-type pattern and the Ki-67 index reached 70%. This report highlights that secondary PPD must be considered in patients with refractory perianal symptoms even without a detectable mass, emphasizing that rigorous pathological examination and specific IHC markers are paramount for identifying occult primary lesions and ensuring optimal surgical outcomes.