# Therapeutic Algorithm for Extramammary Paget Disease: Experience in a Dermatology Referral Center in Western Mexico

## TL;DR

This paper presents a diagnostic and treatment algorithm for extramammary Paget disease based on 10 patient cases from a Mexican dermatology center.

## Contribution

A novel diagnostic and therapeutic algorithm for EMPD based on institutional experience and clinical outcomes.

## Key findings

- All 10 cases confirmed primary EMPD with no associated internal malignancies.
- Surgical excision with wide margins was the treatment of choice in all patients.
- A CK7-positive/CK20-negative immunohistochemical profile confirmed primary EMPD in 60% of cases.

## Abstract

Introduction

Extramammary Paget disease (EMPD) is a rare intraepithelial adenocarcinoma that predominantly affects areas rich in apocrine glands. Its chronic and nonspecific clinical presentation frequently leads to misdiagnosis and delayed treatment.

Objective

The primary objective is to describe the clinical, epidemiological, histopathological, and therapeutic characteristics of patients with EMPD treated at a dermatology referral center. The secondary outcome is to propose a diagnostic and therapeutic algorithm based on institutional experience.

Methods

A single-center, retrospective, observational case series was conducted at the Instituto Dermatológico de Jalisco. All patients with histopathologically confirmed EMPD diagnosed between 2011 and 2025 were included. Demographic, clinical, histopathological, immunohistochemical, and therapeutic data were analyzed. Immunohistochemistry and staging studies were performed selectively based on clinical suspicion of secondary disease.

Result

Ten cases were identified (N = 10). There was a marked female predominance (90%), with a median age of 69 years (range: 57-86). Lesions were primarily located on the vulva (70%), followed by the perianal region (20%) and scrotum (10%). All patients presented with chronic, well-demarcated erythematous plaques. The median diagnostic delay was 20 months (range: 2-60). Immunohistochemistry was performed in six patients (60%), all demonstrating a CK7-positive/CK20-negative profile, confirming primary EMPD in all cases. No associated internal malignancies were identified. All patients underwent wide-margin surgical excision.

Conclusions

EMPD requires high clinical suspicion and early biopsy of persistent genital or perianal lesions. All cases in this series corresponded to primary EMPD with no associated malignancy. Surgical excision remains the standard of care. The proposed algorithm provides a practical, experience-based framework to guide diagnostic evaluation and management in referral centers.