Depigmented extramammary Paget's disease.

BACKGROUND: Depigmented extramammary Paget's disease (EMPD) has been reported in a few cases. Depigmented macules or patches may be the only presenting sign or may coexist with the classical erythematous lesions.

OBJECTIVES: To investigate the occurrence rate and clinical presentation of depigmentation in EMPD.

METHODS: All pathology-proven cases of EMPD diagnosed in our department during 1990-2003 were retrieved. The clinical photographs were reviewed for evidence of local depigmentation. The pathological diagnosis of EMPD in the whitish lesions was confirmed by positive expression of cytokeratin 7 or carcinoembryonic antigen, and/or the presence of intracytoplasmic mucin.

RESULTS: Of 19 cases of EMPD, six (30%) manifested depigmented lesions which were confirmed to be EMPD pathologically. In two patients, the hypopigmentation was associated with erythematous lesions at the initial presentation. In four others, the depigmentation developed later as local recurrence after excision, cryotherapy, photodynamic therapy or radiotherapy. The progressive enlargement of the depigmentation and the appearance of separate new white lesions in these four cases suggested that the localized depigmentation was unlikely to be simple postinflammatory hypopigmentation.

CONCLUSIONS: Our study suggests that depigmented EMPD may not be rare. Localized depigmentation in the genital area can be an early sign of EMPD and its local recurrence. In patients with an established diagnosis of EMPD, appearance of new white lesions and continuous enlargement of depigmented patches should not be dismissed as simple treatment-induced postinflammatory hypopigmentation or another type of hypopigmented lesion without biopsy confirmation.