Supplementary Material for: Spontaneously regressing penile extramammary Paget disease without recurrence of primary urothelial carcinoma: a case report

Introduction: Secondary extramammary Paget disease (EMPD) is a rare cutaneous malignancy that typically manifests on apocrine-rich skin that originates from an underlying adenocarcinoma. It has a low chance of further metastasizing and treatment is recommended. Case Presentation: We present a case of an 86-year-old man with a history of bladder carcinoma that was successfully treated and in remission for 4 years, who presents with an asymptomatic rash on the glans penis. Histopathology and immunohistochemistry confirmed secondary EMPD of urothelial origin. Cancer screening was negative and this was declared secondary EMPD without recurrence of primary malignancy. The patient declined surgical and pharmacologic treatment. After 1 year, the lesion spontaneously resolved with no recurrence. Conclusion: Secondary EMPD can present without underlying malignancy and may spontaneously regress. This may be a rare phenomenon when there is no recurrence of underlying malignancy. Treatment decisions should be made in the context of thorough goals of care discussions. Further observation of this phenomenon is required to guide management plans.

引言：继发性乳房外佩吉特病（Secondary extramammary Paget disease, EMPD）是一种罕见的皮肤恶性肿瘤，通常好发于顶泌汗腺丰富的皮肤区域，起源于潜在的腺癌。该肿瘤转移风险较低，推荐采取治疗措施。
病例报告：本文报告1例病例：患者为86岁男性，有膀胱癌病史，经治疗后病情缓解达4年，此次因龟头出现无症状皮疹前来就诊。经组织病理学与免疫组化检查，证实为尿路上皮来源的继发性EMPD。癌症筛查结果为阴性，确诊为继发性EMPD且未发现原发恶性肿瘤复发。患者拒绝接受手术及药物治疗。随访1年后，皮损自行消退且未见复发。
结论：继发性EMPD可在无潜在恶性肿瘤的情况下出现，且可能发生自行消退。在未出现原发恶性肿瘤复发的背景下，该现象较为罕见。治疗决策应结合充分的照护目标沟通讨论后制定。仍需对该现象开展进一步观察，以指导临床治疗方案的制定。