Vasyl V. OstafiichukSurgical Oncologist · National Cancer Institute of Ukraine
Skin cancerRare tumoursResourcesConsultationУкраїнська
Rare skin cancers

Extramammary Paget disease

A rare intraepidermal adenocarcinoma of apocrine-bearing sites. A central question is whether disease is primary cutaneous EMPD or secondary spread from an internal carcinoma.

Clinical appearance of vulvar extramammary Paget disease
Clinical EMPD. A persistent erythematous eczema-like lesion may be mistaken for dermatitis for a prolonged period.Londero AP et al. / Wikimedia Commons, CC BY-SA 4.0.
Extramammary Paget disease histology
EMPD, H&E. Large atypical Paget cells within the epidermis; final interpretation requires clinicopathologic and IHC correlation.Nephron / Wikimedia Commons, CC BY-SA 3.0.

Presentation

Persistent erythematous, pruritic or eczema-like lesions in vulvar, perianal, groin or other apocrine-bearing sites may be treated as dermatitis for months. Persistent unilateral disease or failure to respond deserves biopsy.

Primary versus secondary EMPD

Immunohistochemistry and anatomic site help determine whether disease is primary cutaneous EMPD or epidermal spread from colorectal, urothelial or another internal carcinoma.

Internal-malignancy screening

Screening should be anatomically directed rather than identical for every patient.

Depth of invasion and nodes change the pathway

Intraepidermal EMPD and invasive adenocarcinoma carry different risks. Pathology should clarify dermal invasion, lymphovascular invasion and other features that increase regional or systemic risk. Suspicious nodes require confirmation; SLNB may be considered selectively in invasive/high-risk scenarios rather than applied routinely to every patient.

In situ / intraepidermal

The priority is local control and excluding secondary EMPD.

Invasive

Depth, nodal risk and more complete staging become increasingly important.

Nodal/metastatic

Systemic planning may incorporate HER2 and other potentially actionable features.

Local treatment

Surgery with reliable margin control remains important in localized disease. Subclinical extension can exceed visible borders.

HER2 and systemic therapy

A subset of advanced EMPD is HER2-positive. Prospective HER2-targeted data are emerging, but this applies to biomarker-selected advanced disease rather than routine localized EMPD.

Practical point: HER2 testing is particularly relevant in unresectable, recurrent or metastatic EMPD when the result may open a targeted treatment option. It does not replace adequate local control for localized operable disease.

HER2 landscape 2026

A 2026 review summarizes emerging experience with antibodies, tyrosine-kinase inhibitors and antibody-drug conjugates in HER2-positive EMPD. Because the disease is rare, the evidence base still relies on small series, case reports and early prospective data, so molecular selection and MDT review remain essential.

HER2 inhibitors in EMPD, 2026.

Current evidence

Guideline 2025 · Anatomic screening guidance · HER2DOC phase II.