Pseudomyxoma Peritonei With Suspected Gastroesophageal Junction Mass: A Rare and Atypical Presentation.

Pseudomyxoma peritonei (PMP) is a rare clinical entity characterized by the accumulation of mucinous ascites and peritoneal implants, most commonly originating from appendiceal or ovarian neoplasms. Its diagnosis is often delayed due to vague and nonspecific symptoms. We report the case of a 75-year-old female who presented with diffuse abdominal pain, melena, and significant weight loss. Clinical evaluation revealed ascites, and imaging suggested a possible gastroesophageal (GE) malignancy. Ascitic fluid analysis was inconclusive. Due to the markedly distended abdomen and unclear primary pathology, a diagnostic laparotomy was performed. Intraoperatively, mucinous ascites and widespread peritoneal deposits were noted without an identifiable primary tumor. Histopathological analysis confirmed PMP. MRI and contrast-enhanced CT (CECT) are valuable tools in the diagnosis of PMP, with characteristic features such as visceral scalloping aiding differentiation from other ascitic conditions. Cytoreductive surgery (CRS) with hyperthermic intraperitoneal chemotherapy (HIPEC) remains the gold standard for treatment. However, in this case, the patient's condition rapidly deteriorated, and she succumbed to multiorgan dysfunction before definitive therapy could be initiated. This report underscores the importance of early suspicion, timely surgical intervention, and referral to specialized centers in managing atypical presentations of PMP.