A 53-year-old previously healthy white man complains of a pruritic rash on his perineum and anus that he has had for 1 year; the rash is unresponsive to treatment with
topical antifungals and topical steroids. Physical examination shows the lesion measures 50 cm2, is erythematous, and has small erosions present within the plaque (Figure 1). No other lesions are found. Histologic analysis of a biopsied specimen (Figure 2) confirms the diagnosis.
Quiz Answer
Extramammary Paget's disease (EMPD)—In our patient, the perineal location, superficial erosions, and recalcitrant nature of his condition was suspicious for EMPD. The biopsy findings confirmed the diagnosis.
Crocker first described EMPD involving the penis and scrotum in 1889. EMPD is rare in patients younger than 50 years; the average age at onset ranges between 62 and
65 years. The incidence is greater among women (female-to-male ratio, 1.4:1).1 The exact origin of the pagetoid cells is not known, but areas of dense apocrine glands (ie, vulva, penis, scrotum, anus, perineum, and axillae) are preferentially involved.2
Patients with EMPD usually present with eczematous-appearing lesions, but these do not respond to topical steroids or emollients. Pruritus is the most common symptom,
but pain, erosions, maceration, and bleeding are seen in longstanding lesions, as was the case in this patient. The condition generally begins with hypopigmented
macules, which then progress to erythematous patches and plaques typical of this condition.
Pagetoid cell cytoplasm is pale-staining on standard hematoxylin and eosin sections, and mitotic spindles are present. The 3 subtypes of EMPD are3:
- EMPD cells in the upper epithelium, without malignant association; estimated incidence, 46% to 52%
- Epithelial form with adnexal carcinoma; estimated incidence, 24%
- EMPD with visceral malignancy; estimated incidence, 12% to 18%.
Because of the multifactorial nature of EMPD and its association with malignancy, the diagnosis requires several procedures, including a skin biopsy of the affected
lesion, colorectal examination (manual and by colonoscopy), radiography, lymph node review, and standard screening for colorectal, bladder, renal, prostate, uterine, breast, hepatic, pancreatic, and adnexal carcinomas.
The treatment of choice for EMPD is surgical excision, with wide margins, although other therapies have shown good outcomes, including topical immunomodulators,
such as imiquimod.4 Delineating the extent of the disease, with risk stratification, is pivotal, because EMPD can recur in one third of patients.3 Most cases of primary EMPD that is limited to the epidermis or adnexal epithelium have a good prognosis. In contrast, the prognosis of EMPD that is associated with subjacent adnexal carcinoma or visceral carcinoma is poor, because metastasis occurs frequently.
Lichen simplex chronicus can be distinguished from EMPD by the clinical history of habitual rubbing or scratching to relieve the pruritus. The lesions are slightly erythematous, scaly, well-demarcated, firm, rough plaques, with exaggerated skin lines, and are localized to easily reached areas.
Mycosis fungoides is a malignant lymphoma characterized by the expansion of a CD4+ memory T-cell clone within the upper dermis. Similar to EMPD, patch-phase mycosis fungoides is characterized by flat, usually erythematous, pruritic, scaly macules that may be single or multiple. The histologic appearance, however, is characterized by hyperchromatic, irregularly shaped cerebriform T cells that help to differentiate it from EMPD.
Bowen's disease is a squamous-cell carcinoma in situ, with the potential for significant lateral spread. A sharply demarcated, irregular border usually defines the erythematous, scaly plaques that may become hyperkeratotic, crusted, fissured, or ulcerated.
References
- Lupton GP, Graham JH. Mammary and extramammary Paget's disease. In: Cancer of the Skin. Friedman RJ, Rigel DS, Kopf AW, eds. Philadelphia, Pa: W.B. Saunders; 1991:217.
- van der Putte SC, van Gorp LH. Adenocarcinoma of the mammarylike glands of the vulva: a unifying sweat gland carcinoma of the vulva, carcinoma of the supernumerary mammary glands and extramammary Paget's disease. J Cutan Pathol. 1994;2:157-163.
- Chanda JJ. Extramammary Paget's disease: prognosis and relationship to internal malignancy. J Am Acad Dermatol. 1985;13:1009-1014.
- Zampogna JC, Flowers FP, Roth WI, et al. Treatment of primary limited cutaneous extramammary Paget's disease with topical imiquimod monotherapy: two case reports. J Am Acad Dermatol. 2002;47(4 suppl): S229-S235.
