Diagnostic Pitfalls in Peritoneal Carcinomatosis: A Case of Pseudomyxoma Peritonei.

Pseudomyxoma peritonei (PMP) is a rare pathological condition posing significant diagnostic and management challenges. This article presents a clinical case of a 58-year-old female who was initially diagnosed with stage III primary peritoneal carcinoma. Following neoadjuvant chemotherapy, a diagnostic re-evaluation was performed with histopathological and immunohistochemical review of biopsy specimens, which led to a revised diagnosis of mucinous carcinoma with features consistent with PMP. The patient subsequently underwent complete cytoreductive surgery (CRS) followed by hyperthermic intraperitoneal chemotherapy (HIPEC). She has remained disease-free for 12 months post-operatively. This case illustrates the crucial role of pathological assessment in guiding treatment for PMP and demonstrates favorable long-term outcomes with aggressive CRS and HIPEC in appropriately selected patients.