Concurrent chemoradiotherapy for metastatic vulvar extramammary Paget's disease involving supraclavicular nodes: a case report.

Extramammary Paget's disease (EMPD) is a rare adenocarcinoma with a poor prognosis when invasive. Here, we report an exceptionally rare case of invasive vulvar EMPD in a 70-year-old woman who presented with extensive lymphadenopathy involving the inguinal, pelvic, para-aortic, and left supraclavicular regions. Histopathology confirmed dermal and lymphovascular invasion. Given the systemic nodal spread, the patient underwent definitive concurrent chemoradiotherapy (CCRT) with weekly cisplatin. Radiotherapy was delivered to the inguinal-to-paraaortic nodes at 57.6 Gy in 32 fractions and to the supraclavicular nodes at 51.0 Gy in 17 fractions. Follow-up imaging 6 months after treatment demonstrated a complete response per Response Evaluation Criteria in Solid Tumor criteria. This case is notable because supraclavicular involvement in EMPD is extremely rare and usually reflects advanced systemic dissemination. Our findings suggest that intensive CCRT may achieve excellent locoregional and systemic disease control, supporting its potential role as an effective primary treatment option for patients with advanced metastatic EMPD.