Extramammary Paget's/Paget's Disease

Overview

The diagnosis of Paget's disease or extramammary Paget's is made when Paget cells are identified in histopathologic specimens from involved skin. The term Paget's disease is used when the cutaneous lesion is identified involving the nipple of the breast, whereas extramammary Paget's is used when the skin lesion is identified in an anogenital location.

First Steps

1. Evaluate the patient for an underlying carcinoma of the breast (Paget's) or sweat gland, lower genitourinary (GU) tract, or lower gastrointestinal (GI) tract (extramammary Paget's). Mammary Paget's is almost always associated with an underlying carcinoma. The data on extramammary Paget's are less clear, but between 25% and 50% have an associated carcinoma. A careful lymph node evaluation is essential. Immunoperoxidase markers on paraffin-fixed tissue can be used to identify the source of the primary carcinoma or confirm that the lesion arose in the skin locally.
2. Refer patients with Paget's disease of the breast to a general surgeon with experience in the management of breast cancer.
3. If underlying carcinoma is found in a case of extramammary Paget's referral to an appropriate surgeon (ie, GU tract to a urologist, female genital tract to a gynecologic cancer specialist, and GI tract to a general surgeon) is indicated.
4. Extramammary Paget's lesions, if small and not associated with underlying carcinoma, may be totally excised. Careful evaluation of the margins is essential. Some dermatologic micrographic surgeons believe that they can remove these lesions and spare tissue by tracing the involvement.

Alternative Steps

If surgery is not possible due to the size of the lesion or the patient's overall health, a trial of imiquimod 5% cream applied daily (or as maximally as tolerated) should be considered. Apply the cream 2 cm beyond the visible lesion. After the lesion has been clinically resolved, a biopsy to confirm a cure is suggested.

Subsequent Steps

1. If imiquimod alone is ineffective, imiquimod plus tretinoin cream plus 5% 5-fluorouracil cream can be used.
2. Photodynamic therapy can be considered in patients who are not candidates or if the above treatments fail.
3. Careful follow-up is essential, as the recurrence rate is high following all forms of therapy.

Pitfalls

1. Failure to diagnose a recalcitrant, apparently eczematous, lesion involving the nipple or anogenital area as Paget's disease or extramammary Paget's is possible.
2. Failure to evaluate and follow up regularly for underlying malignancy.
3. All forms of therapy are associated with high recurrence rates. Therapy should be determined in consultation with appropriate surgical specialists in a Tumor Board setting.