Chapter 88: Paget Disease of The External Genitalia

PATIENT STORY

A 60-year-old woman presented with vulvar pruritus for 1 year that is now constant. On physical examination, there is one large red lesion surrounded by white epithelium (Figure 88-1). A 3-mm punch biopsy was done of the white island within the red lesion using local anesthesia. The pathology showed Paget disease of the vulva. The patient underwent a wide local excision of the involved area and no malignancy was found.

INTRODUCTION

Paget disease of the external genitalia is an uncommon primary cutaneous adenocarcinoma of apocrine gland-bearing skin. The most commonly involved site is the vulva, although perineal, perianal, scrotal, and penile skin may also be affected. Less commonly, the axilla, buttocks, thighs, eyelids, and external auditory canal may be found.¹ It is morphologically and histologically identical to Paget disease of the nipple except for the anatomic location.

SYNONYMS

Extramammary Paget disease.

EPIDEMIOLOGY

• The incidence of extramammary Paget disease is approximately is 0.7 per 100,000 persons per year in Europe.²

• It accounts for 1–2% of all vulvar malignancies.^2,3

• The female-to-male ratio is 3 to 4.5 to 1.⁴

• Most patients are white and in their sixth or seventh decade of life.⁵

• Approximately 4% to 25% of patients with genital Paget disease have an underlying neoplasm.^5-7 Associated malignancies include carcinomas of the Bartholin glands, urethra, bladder, vagina, cervix, endometrium, or adnexal apocrine tissue. Only a minority of cases represent a direct extension of an underlying carcinoma.

• Perianal Paget disease (Figure 88-2) is associated with underlying colorectal carcinoma in 25% to 35% of cases.

ETIOLOGY AND PATHOPHYSIOLOGY

• Extramammary Paget disease probably arises from apocrine gland tissue, usually as a primary cutaneous adenocarcinoma. The epidermis becomes infiltrated with neoplastic cells showing glandular differentiation. The tumor cells may originate from apocrine gland ducts or from keratinocytic stem cells.

RISK FACTORS

• Extramammary Paget disease should be considered in any patient with chronic dermatitis of the groin, vulva, scrotal, or perianal area. Patients with Paget disease of the external genitalia often present with nonresolving eczematous lesions in the groin, genitalia, perineum, or perianal area.^2,8

DIAGNOSIS

CLINICAL FEATURES

• Lesions present on the vulva as geographic red ...