Peritoneal Surface Malignancies

Excerpt

Peritoneal surface malignancies (PSMs) are a heterogeneous group of tumors that arise from or spread to the peritoneum, including primary peritoneal tumors, pseudomyxoma peritonei (often originating from the appendix), and peritoneal carcinomatosis from gastrointestinal or gynecologic primaries. Although exact incidence rates are challenging to define, PSMs can account for a substantial proportion of advanced intra-abdominal malignancies. These malignancies are often multifocal, manifesting as widespread nodules or mucinous deposits within the peritoneal cavity, and can lead to significant morbidity through complications, eg, malignant ascites, bowel obstruction, and malnutrition.

PSMs can be broadly divided into 3 main categories—mucinous, nonmucinous, and primary peritoneal—each with distinct histopathologic features, clinical behavior, and metastatic potential. Mucinous tumors tend to have an indolent course. However, they can accumulate large volumes of intraperitoneal mucin. At the same time, high-grade peritoneal carcinomatosis can be more aggressive, and primary peritoneal mesothelioma remains relatively rare but may present a challenging clinical course. Diagnosis of PSMs typically involves a combination of cross-sectional imaging, histopathologic evaluation of peritoneal implants, and tumor markers such as CEA or CA-125. Computed tomography (CT) and magnetic resonance imaging (MRI) help delineate the distribution of disease, while laparoscopic assessment can confirm the extent and allow for tissue sampling.

Treatment strategies depend on the tumor's origin, grade, and disease burden. For many patients with PSMs, complete cytoreductive surgery (CRS) combined with hyperthermic intraperitoneal chemotherapy (HIPEC) offers the best chance of prolonged survival. In cases of unresectable or recurrent peritoneal surface malignancies, systemic chemotherapy and targeted therapies are viable treatment options. Additionally, palliative measures may be crucial to manage complications like bowel obstruction and refractory ascites. Given the heterogeneity of these malignancies, an interprofessional approach is imperative to optimize patient outcomes. This resource will aid in understanding the classification, pathogenesis, diagnostic tools, and therapeutic modalities in managing patients with PSMs.