Background: Primary peritoneal serous papillary carcinoma is a rare malignant epithelial tumor which was first described in 1959. Peritoneal serous papillary carcinoma arises from the peritoneal epithelium and originates from a single or multicentric focus of the peritoneum involving the peritoneum of the abdomen and pelvis. The involvement of retroperitoneal lymph nodes occurs in 64% of the patients diagnosed with this malignancy. So far, there is no report about inguinal lymph node metastasis in this disease. Case Report: We present a rare case of a 63-year-old female patient who developed singular inguinal lymph node metastasis 1 year after cytoreductive surgery and hyperthermic intraperitoneal chemotherapy due to peritoneal serous papillary carcinoma. The lymph node metastasis was found by computed tomography (CT) scan and was resected and histologically confirmed. The postoperative course was uneventful, and the patient was discharged on postoperative day 1. The last CT scan 24 months after initial cytoreduction and 12 months after lymph node resection showed no further tumor recurrence. Conclusion: This case report should raise the awareness of potentially unexpected presentation of extraperitoneal metastasis and highlights the importance of patient follow-up including clinical examination and CT scans of thorax/abdomen/pelvis following a systematic schedule.
