Hypopigmentation in Extramammary Paget Disease Is an Important Prognostic Factor for High Recurrence Rate and Poor Surgical Outcome.

BACKGROUND Several studies have reported the presence of hypopigmentation in extramammary Paget disease (EMPD). However, an in-depth analysis regarding its clinical implication is lacking. OBJECTIVE To evaluate the clinical characteristics of EMPD in the Korean population and to determine the implication of hypopigmentation on clinical outcomes. METHODS We retrospectively reviewed 124 cases of EMPD who underwent surgical treatment from a single tertiary hospital from December 2005 to March 2019. Baseline characteristics of the patients and hypopigmentation patterns were analyzed. Moreover, the number of stages of Mohs micrographic surgery (MMS) and recurrence rate were evaluated in relation to the hypopigmentation. RESULTS A total of 67.7% (n = 84) of the patients showed hypopigmentation. The adjusted odds ratio for recurrence in the hypopigmented group was 5.980, which was statistically significant (95% confidence interval = 1.347-26.553, p-value = 0.019). Furthermore, the average number of MMS stages was 2.92 in the hypopigmentation group, compared with 1.82 in the nonhypopigmentation group (p-value = .0016). CONCLUSION Hypopigmented lesions may disguise the tumor margin, thus raising the recurrence rate after surgery and the number of stages of MMS. The hypopigmentation status must be considered when deciding the surgical margin.