Abstract
Primary peritoneal adenocarcinoma (PPA) is a rare and aggressive malignancy that closely resembles high-grade serous ovarian carcinoma but originates from the peritoneal lining with minimal ovarian involvement. We present the case of a 72-year-old female patient with a history of endometrial cancer who developed progressive ascites, recurrent hospitalizations, and a hypercoagulable state. Imaging revealed peritoneal carcinomatosis, and paracentesis confirmed high-grade serous carcinoma through immunohistochemical staining. Despite initial plans for chemotherapy, treatment was deferred for outpatient initiation. Due to disease progression, she underwent cytoreductive surgery with tumor debulking, but pathology confirmed metastatic spread. Postoperative complications included hypotension and ileus, which extended hospitalization. This case highlights the diagnostic and therapeutic challenges of PPA, emphasizing the need for a multidisciplinary approach to optimize patient outcomes.