Extramammary Paget’s disease (EMPD) is a rare malignancy, and little was known about its prognostic factors and optimal treatment. In the current study, we aimed to discuss clinical and pathological features of scrotal EMPD and determine the prognostic factors for cancer-specific survival and local recurrence. A total of 206 patients with scrotal EMPD lesions surgically treated at our institute were studied. All clinical and pathological data were reviewed. Immunohistochemical staining of TP53 and Ki67 was examined as well. At the last follow-up, 175 patients (84.95%) were alive. Twelve patients (5.83%) had died of the disease due to distant metastases. Fifteen patients (7.28%) developed local recurrences of scrotal EMPD. Ki67 expression was significantly elevated in patients with wide horizontal invasion (P = 0.003). In univariate analysis, high invasion level, presence of nodule, presence of lymphovascular invasion, adnexa invasion, lymph node metastasis and high p53 expression were significant factors for poor cancer-specific survival. In multivariate analysis, high p53 expression was significantly correlated with poor cancer-specific survival. Wide horizontal invasion was independently correlated with local recurrence-free survival of scrotal EMPD. In conclusion, wide horizontal invasion is an independent risk factor for local recurrence-free survival in the patients with scrotal EMPD.
Extramammary Paget’s disease (EMPD) is a rare cancer. Although EMPD is usually noninvasive and treated with local therapy, once metastatic the prognosis of EMPD is poor and treatment options are limited. We report a case of a complete response to single agent trastuzumab in a hemodialysis patient with metastatic Her2/neu overexpressed EMPD of the scrotum. Molecular profiling of his case as well as 12 other EMPD and 8 mammary Paget disease (MPD) cases was completed and revealed multiple biomarker aberrations. Overexpression of Her2 was frequently noted (30%–40%) in both EMPD and MPD patients and when present can be effectively treated with Her2 targeted agents. Trastuzumab therapy can be safely utilized in a hemodialysis patient. In addition, multiple protein overexpression and loss were seen in EMPD including PD-1, PD-L1, PTEN, and AR as well as PIK3CA mutation. These findings may lead to possible therapeutic interventions targeting these pathways in a disease with few effective treatment options.